How important (or not) is it to have a Rem 700 action trued and(or?) blueprinted?

[FredH]

Yes it does, but it’s more like run it up to temp, let it soak at temp for a fairly long period of time, then let it cool. Not exactly your process. They say “The devil is in the details” but what do I know?

Have you ever noticed or heard of a barrel that shoots better after being shot a couple hundred times? I guess it is a mystery.

 

[NorthIdahoDude]

Thread Resurrection:

TL;DR - I'm starting to think there is something to this 'truing up the action' business. I'm on the 3rd barrel in this action that shoots identically to the first 2. WTF? Also, Criterion gets huge props for top notch customer service!

The TL;

So, I talked to Criterion about the 30-06 barrel asking if they had any tips/tricks/more things to try, and explained what I had tried so far, and they came back absolutely adamant I ship the barrel back to them. After inspection, they found nothing out of spec or otherwise that they thought could cause the accuracy issues I was seeing, however, they were't having it that I wasn't getting what I wanted out of it, so they insisted on replacing the barrel, not returning it. All else aside - that's absolutely top notch customer service, and Criteron goes in my book as one of the Good Guys(tm).

What I had really wanted in the 1st place was a 280AI in 1:8 twist, but Northland Shooters doesn't stock those, and I love me some 30-06, so that's what I got. Since Criteron would make anything I wanted, I opted for a 1:8 twist 26 inch 280AI sporter, which showed up at my door a few weeks later (again, top notch customer service!!!)

Good components matter, as do choices that are 'known good' for a given cartridge, so I started with:

Brass: Peterson 280AI
Primers: Federal 210M
Powder: H4831SC
Bullets: 162 and 175 ELD-X's and 160 Accubonds.
Seating depth: .020 off the lands (which in the Criterion 'match' chamber is perfection - bottom of bullet shank +/- a whisker of being exactly at the bottom of the case neck in all cases)

First trip to the range, I went with a modest charge of 56.3 grains and 162 ELD-X's and Accubond's on deck. Accubonds were horrible (north of 2 MOA), but the ELD-X's looked promising at just over 1MOA, but only for 5 rounds with a mean radius of .44, which would indicate a real 'cone of fire' closer to 1.75 MOA or so. Hmmm...

2nd trip to the range, heated up the 162 ELD-X load a bit to 58 (still well under max) for a velocity average of 2844, along with some 175 ELD-X's at 57 grains. It was raining and cold and windy and miserable at the range, so I shot at 50 instead of 100 (adjustable parallax, so not unreasonabe). 5 shots of each, all came in a hair over 1MOA, but again with mean radius in the 0.40 to 0.5 range.

3rd trip with a mix of 162 and 175's, the 162's (at 100 again) and ran 10 rounds of the 162 this time - which came in at 2 MOA, about what I had expected from the mean radii I've been seeing so far. 5 rounds of the 175 again came in a bit over an inch, but mean radius of .5.

4th trip with 10 175's, and they came in a bit over 2 inches... just for grins, i brought the 7x57 that day, and pounded 3 into one ragged hole of 0.25 MOA with a mean radius of 0.15. Nope, the boy can actually shoot, so it's not me.

I've stopped going to the range and am just backyard testing at 50 yards, and 140 NBT's, 150 NBT's, and 140 TGK's, all in the same ballpark for accuracy.

I have a hard time believing I got 2 barrels in a row from Criterion, in substantively different cartridges, that have both been almost identical accuracy profile. The OEM barrel had some rusty spots in the bore, so I never expected it to be that great, but it honestly shot about exactly the same - 1.7 to 2 MOA with good components, worse with less good components. So ever single barrel ever screwed into this action shot the same.... hmmm.....

Notes to re-hash for the people who will start asking the usual questions:

Recoil - this is a 10.3lb gun I'm running somewhat mild loads in, recoil is around 15-16lbs according to recoil calculators, identical to my 7x57 which is a laser beam, and less than my Stag Pursuit in 308, which is also doing very very well for me, and way less than my old 308 Tikka Lite with the 3-9 that used to shoot 1/2 inch groups for me back in Canuckistan.

Loading techinque - same dude doing the same things that get me really good to downright fantastic accuracy in some of my other guns.

Scope - that scope came off my Savage 7x57 (since sold) that shot 1/2 MOA, confident it works.

Screw torque - for all the things has been checked, re-checked, and re-re-checked.

Bedding - It's currently in a Magpul Hunter with the solid aluminum bedding block (previously have run it in a SPS stock that's been bedded with JB Weld - shot the same in that).

Scope Alignment - scope bases are very out of alignment on this gun, so I'm using Burris Signature rings with the inserts to avoid torquing the scope.

Scope bases: solid steel, properly loc-tited and torqued.

So.... unless someone's got some other ideas, I can't think of any possible culprits other than the action itself having some flaw that's contributing to very "meh" accuracy....

The only real test, I s'pose is to take it in to a smith and drop ANOTHER $200-$300 or whatever on it having it fully trued up, and try the exact same barrel and loads again, which I'm kind of loathe to do at this point after what I've spent already...

Anyway - that's my story - input from those more knowledgeable than me is more than welcome (and input from those not more knowledgeable than me is welcome also, as long as you're vaguely polite, LOL).

 

[Gobihawk]

Lots of good information. I only own 1 700. Off base but something I ran into with my 243. Three shot groups were 1.5. Checked trigger pull. Was 4.5 Oz. Wouldn't adjust lower. Put a Timney trigger in set at 2 Oz. Groups are under .5. Something to think about.

 

[NorthIdahoDude]

Lots of good information. I only own 1 700. Off base but something I ran into with my 243. Three shot groups were 1.5. Checked trigger pull. Was 4.5 Oz. Wouldn't adjust lower. Put a Timney trigger in set at 2 Oz. Groups are under .5. Something to think about.

2 stage Trigger tech, around 2.5lbs total weight. One of the better triggers I've ever shot.

 

[TaperPin]

Thread Resurrection:

TL;DR - I'm starting to think there is something to this 'truing up the action' business. I'm on the 3rd barrel in this action that shoots identically to the first 2. WTF? Also, Criterion gets huge props for top notch customer service!

The TL;

So, I talked to Criterion about the 30-06 barrel asking if they had any tips/tricks/more things to try, and explained what I had tried so far, and they came back absolutely adamant I ship the barrel back to them. After inspection, they found nothing out of spec or otherwise that they thought could cause the accuracy issues I was seeing, however, they were't having it that I wasn't getting what I wanted out of it, so they insisted on replacing the barrel, not returning it. All else aside - that's absolutely top notch customer service, and Criteron goes in my book as one of the Good Guys(tm).

What I had really wanted in the 1st place was a 280AI in 1:8 twist, but Northland Shooters doesn't stock those, and I love me some 30-06, so that's what I got. Since Criteron would make anything I wanted, I opted for a 1:8 twist 26 inch 280AI sporter, which showed up at my door a few weeks later (again, top notch customer service!!!)

Good components matter, as do choices that are 'known good' for a given cartridge, so I started with:

Brass: Peterson 280AI
Primers: Federal 210M
Powder: H4831SC
Bullets: 162 and 175 ELD-X's and 160 Accubonds.
Seating depth: .020 off the lands (which in the Criterion 'match' chamber is perfection - bottom of bullet shank +/- a whisker of being exactly at the bottom of the case neck in all cases)

First trip to the range, I went with a modest charge of 56.3 grains and 162 ELD-X's and Accubond's on deck. Accubonds were horrible (north of 2 MOA), but the ELD-X's looked promising at just over 1MOA, but only for 5 rounds with a mean radius of .44, which would indicate a real 'cone of fire' closer to 1.75 MOA or so. Hmmm...

2nd trip to the range, heated up the 162 ELD-X load a bit to 58 (still well under max) for a velocity average of 2844, along with some 175 ELD-X's at 57 grains. It was raining and cold and windy and miserable at the range, so I shot at 50 instead of 100 (adjustable parallax, so not unreasonabe). 5 shots of each, all came in a hair over 1MOA, but again with mean radius in the 0.40 to 0.5 range.

3rd trip with a mix of 162 and 175's, the 162's (at 100 again) and ran 10 rounds of the 162 this time - which came in at 2 MOA, about what I had expected from the mean radii I've been seeing so far. 5 rounds of the 175 again came in a bit over an inch, but mean radius of .5.

4th trip with 10 175's, and they came in a bit over 2 inches... just for grins, i brought the 7x57 that day, and pounded 3 into one ragged hole of 0.25 MOA with a mean radius of 0.15. Nope, the boy can actually shoot, so it's not me.

I've stopped going to the range and am just backyard testing at 50 yards, and 140 NBT's, 150 NBT's, and 140 TGK's, all in the same ballpark for accuracy.

I have a hard time believing I got 2 barrels in a row from Criterion, in substantively different cartridges, that have both been almost identical accuracy profile. The OEM barrel had some rusty spots in the bore, so I never expected it to be that great, but it honestly shot about exactly the same - 1.7 to 2 MOA with good components, worse with less good components. So ever single barrel ever screwed into this action shot the same.... hmmm.....

Notes to re-hash for the people who will start asking the usual questions:

Recoil - this is a 10.3lb gun I'm running somewhat mild loads in, recoil is around 15-16lbs according to recoil calculators, identical to my 7x57 which is a laser beam, and less than my Stag Pursuit in 308, which is also doing very very well for me, and way less than my old 308 Tikka Lite with the 3-9 that used to shoot 1/2 inch groups for me back in Canuckistan.

Loading techinque - same dude doing the same things that get me really good to downright fantastic accuracy in some of my other guns.

Scope - that scope came off my Savage 7x57 (since sold) that shot 1/2 MOA, confident it works.

Screw torque - for all the things has been checked, re-checked, and re-re-checked.

Bedding - It's currently in a Magpul Hunter with the solid aluminum bedding block (previously have run it in a SPS stock that's been bedded with JB Weld - shot the same in that).

Scope Alignment - scope bases are very out of alignment on this gun, so I'm using Burris Signature rings with the inserts to avoid torquing the scope.

Scope bases: solid steel, properly loc-tited and torqued.

So.... unless someone's got some other ideas, I can't think of any possible culprits other than the action itself having some flaw that's contributing to very "meh" accuracy....

The only real test, I s'pose is to take it in to a smith and drop ANOTHER $200-$300 or whatever on it having it fully trued up, and try the exact same barrel and loads again, which I'm kind of loathe to do at this point after what I've spent already...

Anyway - that's my story - input from those more knowledgeable than me is more than welcome (and input from those not more knowledgeable than me is welcome also, as long as you're vaguely polite, LOL).

It also drives me nuts when trying to fix something along those lines where it should shoot better, or at least my expectations were it would make smaller groups. Personally, I’ve found it worthwhile to have a second functionally identical complete rifle. It’s also my primary plinking rifle that gets shot the most, and serves as a backup, but shoots good so some days just shooting it shows the problem is me, or the wiggly bench I’m shooting off of, or it’s more windy down range than at the bench. Just like what you’ve done with other rifles to convince yourself it’s not you, but it also provides a way to test parts on two different receivers. I’m lucky enough to have a known good barrel on the shelf that can be swapped in and it shoots good screwed on to either.

Hope you figure it out and let us know what you came up with.

 

[Kyguy]

Lots of good information. I only own 1 700. Off base but something I ran into with my 243. Three shot groups were 1.5. Checked trigger pull. Was 4.5 Oz. Wouldn't adjust lower. Put a Timney trigger in set at 2 Oz. Groups are under .5. Something to think about.

If someone can't shoot good groups with a good 3lb trigger pull, the rifle isn't the issue.

 

[Formidilosus]

Thread Resurrection:

TL;DR - I'm starting to think there is something to this 'truing up the action' business. I'm on the 3rd barrel in this action that shoots identically to the first 2. WTF? Also, Criterion gets huge props for top notch customer service!

The TL;

So, I talked to Criterion about the 30-06 barrel asking if they had any tips/tricks/more things to try, and explained what I had tried so far, and they came back absolutely adamant I ship the barrel back to them. After inspection, they found nothing out of spec or otherwise that they thought could cause the accuracy issues I was seeing, however, they were't having it that I wasn't getting what I wanted out of it, so they insisted on replacing the barrel, not returning it. All else aside - that's absolutely top notch customer service, and Criteron goes in my book as one of the Good Guys(tm).

What I had really wanted in the 1st place was a 280AI in 1:8 twist, but Northland Shooters doesn't stock those, and I love me some 30-06, so that's what I got. Since Criteron would make anything I wanted, I opted for a 1:8 twist 26 inch 280AI sporter, which showed up at my door a few weeks later (again, top notch customer service!!!)

Good components matter, as do choices that are 'known good' for a given cartridge, so I started with:

Brass: Peterson 280AI
Primers: Federal 210M
Powder: H4831SC
Bullets: 162 and 175 ELD-X's and 160 Accubonds.
Seating depth: .020 off the lands (which in the Criterion 'match' chamber is perfection - bottom of bullet shank +/- a whisker of being exactly at the bottom of the case neck in all cases)

First trip to the range, I went with a modest charge of 56.3 grains and 162 ELD-X's and Accubond's on deck. Accubonds were horrible (north of 2 MOA), but the ELD-X's looked promising at just over 1MOA, but only for 5 rounds with a mean radius of .44, which would indicate a real 'cone of fire' closer to 1.75 MOA or so. Hmmm...

2nd trip to the range, heated up the 162 ELD-X load a bit to 58 (still well under max) for a velocity average of 2844, along with some 175 ELD-X's at 57 grains. It was raining and cold and windy and miserable at the range, so I shot at 50 instead of 100 (adjustable parallax, so not unreasonabe). 5 shots of each, all came in a hair over 1MOA, but again with mean radius in the 0.40 to 0.5 range.

3rd trip with a mix of 162 and 175's, the 162's (at 100 again) and ran 10 rounds of the 162 this time - which came in at 2 MOA, about what I had expected from the mean radii I've been seeing so far. 5 rounds of the 175 again came in a bit over an inch, but mean radius of .5.

4th trip with 10 175's, and they came in a bit over 2 inches... just for grins, i brought the 7x57 that day, and pounded 3 into one ragged hole of 0.25 MOA with a mean radius of 0.15. Nope, the boy can actually shoot, so it's not me.

I've stopped going to the range and am just backyard testing at 50 yards, and 140 NBT's, 150 NBT's, and 140 TGK's, all in the same ballpark for accuracy.

I have a hard time believing I got 2 barrels in a row from Criterion, in substantively different cartridges, that have both been almost identical accuracy profile. The OEM barrel had some rusty spots in the bore, so I never expected it to be that great, but it honestly shot about exactly the same - 1.7 to 2 MOA with good components, worse with less good components. So ever single barrel ever screwed into this action shot the same.... hmmm.....

Notes to re-hash for the people who will start asking the usual questions:

Recoil - this is a 10.3lb gun I'm running somewhat mild loads in, recoil is around 15-16lbs according to recoil calculators, identical to my 7x57 which is a laser beam, and less than my Stag Pursuit in 308, which is also doing very very well for me, and way less than my old 308 Tikka Lite with the 3-9 that used to shoot 1/2 inch groups for me back in Canuckistan.

Loading techinque - same dude doing the same things that get me really good to downright fantastic accuracy in some of my other guns.

Scope - that scope came off my Savage 7x57 (since sold) that shot 1/2 MOA, confident it works.

Screw torque - for all the things has been checked, re-checked, and re-re-checked.

Bedding - It's currently in a Magpul Hunter with the solid aluminum bedding block (previously have run it in a SPS stock that's been bedded with JB Weld - shot the same in that).

Scope Alignment - scope bases are very out of alignment on this gun, so I'm using Burris Signature rings with the inserts to avoid torquing the scope.

Scope bases: solid steel, properly loc-tited and torqued.

So.... unless someone's got some other ideas, I can't think of any possible culprits other than the action itself having some flaw that's contributing to very "meh" accuracy....

The only real test, I s'pose is to take it in to a smith and drop ANOTHER $200-$300 or whatever on it having it fully trued up, and try the exact same barrel and loads again, which I'm kind of loathe to do at this point after what I've spent already...

Anyway - that's my story - input from those more knowledgeable than me is more than welcome (and input from those not more knowledgeable than me is welcome also, as long as you're vaguely polite, LOL).

Scopes fail randomly. If you do not swap another known scope on, you won’t know. Also, ensure that your front base screws aren’t protruding into the barrel or barrel threads- that is common. So too the action screws being a bit too long and protruding.

 

[NorthIdahoDude]

Scopes fail randomly. If you do not swap another known scope on, you won’t know. Also, ensure that your front base screws aren’t protruding into the barrel or barrel threads- that is common. So too the action screws being a bit too long and protruding.

Excellent points.

I've already fixed the action screws, they were definitely too long when I replaced the OEM flat head screws.

I did not think to check the scope base screws, but the base definitely seemed to go on very tight. Also, this is the 2nd set of scope bases (it came with cheap aluminum weavers to begin with, something else I swapped out along the way trying to rule things out). I will check the base screws when I'm putting another scope on it.

This was the "known good" scope I replaced the first scope I had on it with, but that was some time, 200 rounds, and a different barrel ago, so I am going to swap it and see.

I do own a collimator, maybe I'll run a tracking and return to zero test on it before I pull it off.

Probably an even better test would be to slap this barrel on a different action and see, but my other 700 still has the factory barrel on it and shoots pretty good so I hate to pull it apart...

 

[NorthIdahoDude]

Scope tracks straight - swapped it out anyway just to be fo sho.

Trying again tomorrow at the real range, 162 ELD-X, 58.3 H4831SC, once fired + neck sized brass, near 0 run out, 3.487 OAL (.030 off the lands), 210M primers.

 

[TaperPin]

5 shot groups around an inch may be all the barrel(s) were capable of. I’m impressed when mid priced barrels shoot lights out, but we usually hear of the best and worst, rather than an accurate cross section. I’ve had a gunsmith installed $1k barrel shoot mediocre while the next identical barrel was lights out. Hope it works out.

 

[longrangelead]

So, I'm 100% with you on all the tolerances you're outlining here and how bad those are/nobody would consider accepting them for a bench gun or the like. But what I'm asking is, will fixing all that contribute to accuracy to a degree that I might expect a gun would go from say a 2MOA to 3/4 MOA after the fixes? It's one thing to observe 'wow, that was .003 out of spec, which is insanely bad, so I fixed it', and different thing to observe 'that was .003 out of spec, so I fixed it, and nothing else, and after that the gun shot vastly better'.

I just saw this...
There isn't "one thing" that is the magic fix. It's the whole system. Each fix adds to the sum total, or subtracts if left undone.
trueing is just one part. You have to look at the firing pin spring on old rifles, spring strength, firing pin protrusion, firing pin clearance inside bolt, scope bases(I lap and bed ALL Rem's), bedding is stress free, bolt slop in rear bridge, a ground recoil lug...
The barrel: crown, thread fit/clearance to action, chamber aligned with bore, chamber runout, actual chamber dimensions...

I know you said Criterion, I'm just giving you the majority of the list of things that need looked at to make a Rem shoot.

 

[NorthIdahoDude]

5 shot groups around an inch may be all the barrel(s) were capable of. I’m impressed when mid priced barrels shoot lights out, but we usually hear of the best and worst, rather than an accurate cross section. I’ve had a gunsmith installed $1k barrel shoot mediocre while the next identical barrel was lights out. Hope it works out.

I'm not expecting 'lights out', I'm just expecting a cone of fire reasonably better than a factory rifle with the original rusted sewer pipe of a barrel, LOL. I mean, we all hope for lights-out barrels, obviously, but I'd be satisfied with a cone of fire in the 1 MOA range.

 

[NorthIdahoDude]

I just saw this...
There isn't "one thing" that is the magic fix. It's the whole system. Each fix adds to the sum total, or subtracts if left undone.
trueing is just one part. You have to look at the firing pin spring on old rifles, spring strength, firing pin protrusion, firing pin clearance inside bolt, scope bases(I lap and bed ALL Rem's), bedding is stress free, bolt slop in rear bridge, a ground recoil lug...
The barrel: crown, thread fit/clearance to action, chamber aligned with bore, chamber runout, actual chamber dimensions...

I know you said Criterion, I'm just giving you the majority of the list of things that need looked at to make a Rem shoot.

So this is good stuff - some of this I can comment on, if you have any further feedback, I'd appreciate it.

Firing pin spring/pin/etc - this hasn't been looked at, and it's an old enough gun that maybe there's something here. That said, primers look plenty well struck, the dent's are consistent depth and placement (ever so slightly off-set from dead center).

Scope bases are way out of alignment (worst I've ever seen to be honest), but the Burris rings with inserts should resolve that problem (I even mess with the insert offsets till I get the scope close to zero'd in the middle of it's adjustment range). I have verified via witness marks that the scope does not move under recoil.

Bedding is stress free as far as I can tell - in the Magpul stock, I can run either action screw up tight, and when I tighten the other, there's no perceptible movement of the action. The poly stock was bedded to this action, and the way I do those is using WaterWeld and tightening only the front actions screw (and that pretty lightly, just enough to seat the action), to avoid any stress on the action.

This barrel actually has very nice action fit - the OEM barrel had a LOT of slop, where the Criterion has nearly no slop.

The bolt lugs are both fairly evenly worn in. Bolt face is rough and nasty/poorly machined. The bolt itself runs glassy smooth, nearing tikka-smooth, and does not feel to have any significant amount of slop (some of my others have way more).

The scope, when zero'd by live fire, ends up dialed left-of-center about 6 MOA in the collimator, which I presume indicates some runnout of the action threads. Although of all the guns I've ever had, there was 2, maybe 3, where actual zero was zero in the collimator as well (and none of the ones with no runnout there were my most accurate guns).

Rolling fired brass in my old Sinclair runnout gauge, it's good and straight.

Anyway - just throwing all that out in case any of it makes you think "hmmm, that sounds like a more significant problem".

 

[Chris in TN]

So this is good stuff - some of this I can comment on, if you have any further feedback, I'd appreciate it.

Firing pin spring/pin/etc - this hasn't been looked at, and it's an old enough gun that maybe there's something here. That said, primers look plenty well struck, the dent's are consistent depth and placement (ever so slightly off-set from dead center).

I was one of the people who mentioned the FP spring earlier. To be clear, I do not think you can judge the quality of the FP spring by looking at primer indents. If the pin protrudes enough to ignite the primer you're going to have an indent. Your spring would have to weaken to the point of unreliable ignition before you'd suspect it (at least on a newer rifle).

All considered, I don't think that's your problem, but I also don't think you can eliminate it based on the observations you offered.

I suspect you have a scope with an issue that is less than obvious. It would be nice if every scope failure was spectacular and obvious, but that isn't reality from the (very) few failures I've had over the years. A little zero shift here and a bigger than expected group there and suddenly you're pulling your hair out. I'm not an expert there, but the scope problems I've had over the years have generally *NOT* been so major as to be obvious immediately.

 

[TaperPin]

There should be a bookie for poor shooting rifles, setting odds and taking bets. Now that’s something I would get sucked into…and probably lose a good portion of the kids’ inheritance.

 

[NorthIdahoDude]

There should be a bookie for poor shooting rifles, setting odds and taking bets. Now that’s something I would get sucked into…and probably lose a good portion of the kids’ inheritance.

The odds always favor poor shooting rifles, LOL. In my experience, most rifles shoot poorly, just most people don't know it because they get a few good looking 3 shot groups fairly often.

 

[longrangelead]

sounds like your bedding is ok. you can check with a dial indicator attached to barrel or stock with the indicator on the other. Tighten/loosen each action screw separately and the indicator should move .002" or less.


Partially lapped rings to show how out of alignment they are. This one is among the better ones. Using a rail doesn't necessarily fix it because the rail will bend to follow the action. The interface between the rings/rail gives it a place to "hinge" into alignment, but is also a stress point.


Really old rifles and the "J lock" bolts are the worst for fp springs that do this. That wave in the spring rubs inside the bolt causing interference on the firing pin during travel which will affect consistency. I install Tubb dual springs on these to alleviate this.

 

[NorthIdahoDude]

Partially lapped rings to show how out of alignment they are. This one is among the better ones. Using a rail doesn't necessarily fix it because the rail will bend to follow the action. The interface between the rings/rail gives it a place to "hinge" into alignment, but is also a stress point.

Those don't look bad at all, compared to the ones on this rifle, LOL. When I say the bases on this one are bad, I mean VERY VERY bad - easily worst I've ever seen - you don't need any measuring tool other than eyeballs to see they are way off. Without using the Burris Signature rings with the offset shims in them, any scope with less than 60 MOA or so of internal left/right travel cannot be zero'd. I use the offset shims Burris sells to adjust the alignment (+/- 20MOA per shim if I recall correctly) to correct so that the scope can be zero'd without cranking the adjustments hard to one side.

 

[NorthIdahoDude]

I was one of the people who mentioned the FP spring earlier. To be clear, I do not think you can judge the quality of the FP spring by looking at primer indents. If the pin protrudes enough to ignite the primer you're going to have an indent. Your spring would have to weaken to the point of unreliable ignition before you'd suspect it (at least on a newer rifle).

Indeed - enough of you have mentioned the firing pin spring thing, and replacements are cheap (and look like a fairly DIY-able job), so I think I'll give that a try regardless. At this vintage, it's a given that it's not in as good a shape as it left the factory.