Need thought on a load development issue pls

[WTNUT]

Background: Reloading for 40 years, but FAR FAR from expert.
Working up a load for a 338 RUM. The gun likes IMR 7828 ssc with Barnes 265 LRX. I have went overboard working on loads. Tried a ton of powders and OALs with the 265s and 280s. My best load right now is 86.8 gr of IMR 7828 ssc.

Barnes calls for a max load of 85 gr with the 265 bullet.
Nosler calls for a max load of 86.5 gr with a 265 Nosler.
Hodgen calls for a max load of 86 with a 275 bullet.

My question: The gun shot a three shot a .45 4 shot group yesterday. So yes I like that result. HOWEVER, the bolt seemed to open a little rough on one of the shots. The brass shows no signs of an over pressure situation. Nevertheless, I am thinking of dropping the load to 86.5 gr or 86.6 gr. My question is whether that is enough to really help an over pressure situation if one exists, and I am not sure that one does. I really am anxious to finish this load for this new gun. I would like to just convince my self there was no over pressure and go with 86.8, but I know I should just load a few more rounds and see if the gun is just as accurate with 2-3 tenths less powder.


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[WeiserBucks]

If it will ONLY shoot 86.8 then it's not going to be a stable load even it's not over pressure.

 

[35WhelenAI]

My experience: If you're at max, which you are over by any load data you referenced, heat of the day or sitting in the sun on a winter day hunt could put it over the top even more.

A few tenths of a grain drop in a case of that size isn't enough to make a difference. It would be more like dropping back a grain at least. Once pressure signs are seen on any load in a string, that load is already more than a little bit over pressure. Take a bit of velocity loss and an absolutely reliable load 10 times out of 10.

What made you go up to .3 grain over any of the max published loads? Will it only shoot well at that charge? Tenths of a grain difference in a case of that size are immaterial in my experience with respect to major differences in metrics of velocity, accuracy.

Anyway, how does your velocity stack up against the velocity of the load data? Granted there are different barrel lengths, etc.

 

[WTNUT]

If it will ONLY shoot 86.8 then it's not going to be a stable load even it's not over pressure.

I am sorry, but do not understand your point. I can add it shoots other weights of 7828 well, but the 86.8 is the best.
If you can elaborate, I would greatly appreciate it.


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[WTNUT]

My experience: If you're at max, which you are over by any load data you referenced, heat of the day or sitting in the sun on a winter day hunt could put it over the top even more.

A few tenths of a grain drop in a case of that size isn't enough to make a difference. It would be more like dropping back a grain at least. Once pressure signs are seen on any load in a string, that load is already more than a little bit over pressure. Take a bit of velocity loss and an absolutely reliable load 10 times out of 10.

What made you go up to .3 grain over any of the max published loads? Will it only shoot well at that charge? Tenths of a grain difference in a case of that size are immaterial in my experience with respect to major differences in metrics of velocity, accuracy.

Anyway, how does your velocity stack up against the velocity of the load data? Granted there are different barrel lengths, etc.

All good information and what I was looking for. Here are my answers:

1. I really don’t know why I went .3 grains over the highest max load I could find. I was just trying a lot of things.
2. It will shoot at lower weight loads, but that one was the best no doubt.
3. What do you think about trying 86.5 and 86?
4. There are no signs of pressure issues on the brass, is a slightly tight bolt the first sign of over pressure? I have never really had pressure issues, but to be honest I have never pushed any other rifles like this one.


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[WTNUT]

Definitely going to drop the load. Better safe than sorry. The point about gun out in the sun is a good reminder.


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[WeiserBucks]

I am sorry, but do not understand your point. I can add it shoots other weights of 7828 well, but the 86.8 is the best.
If you can elaborate, I would greatly appreciate it.


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What I meant was that if it will shoot well at 86.8 and 86.8 only, then it's not a good load that will perform well over time and various conditions.

Your other posts about dropping the charge and verifying are spot on.

 

[Odd1out]

What brand of brass are you using?

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[Vern400]

I have a similar situation in a smaller cartridge. In my 308 rifle, RL15 gets more precise as the powder charge increases. I had what I thought was a perfect load for hunting. But I did load development at 50° F and at 80° F the load was unsafe. I had to pull 100 bullets, and dropped 0.5 grains down to 46.0 I have been shooting that load now for 30 years and the barrel is shot out.

You're arguing with yourself about 25 fps. That last grain of powder is very inefficient in a magnum cartridge.

Because my past experience I would not settle on a load that was red line or slightly above.

 

[WTNUT]

What brand of brass are you using?

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ADG


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[WTNUT]

Vern400 you are right I am arguing with myself over a little speed.

At times, you need to reach out to some friends like you all to be drug back to your ordinary level of common sense.

I am going to load some more with 7828 in 3 or 5 grain increments and see where we are. I actually expect point of impact to be very close with all which is good.

The gun shoots H1000 as well which I know is more stable as to temperatures than 7828, but the H1000 just isn’t as consistent in terms of accuracy out of this gun.


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[Odd1out]

ADG


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Ok decent brass. What primers are you using?

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[jfk69]

I am going to load some more with 7828 in 3 or 5 grain increments and see where we are.

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I do hope you mean .3 to .5 increments. Otherwise shit‘s gonna get real and real fast lol.

 

[35WhelenAI]

The heavy/tight bolt lift if you have never felt that until working at these load levels, is assured to be a sign of over pressure, don't give it a second thought. You mentioned brass didn't show any pressure signs, which signs are you looking at? I would gather ejector marks on the case head, primer appearance if it's visual you are doing. Some signs you won't see until preparing the brass to fire again. I.E. if the brass was harder to resize or how primer pockets fared.

With what Vern and I said about chasing tenths of a grain in large case, I like your new approach.

Keep in mind he dropped a half grain on a case with half the capacity of the 338 RUM. I would drop a full grain or even two, think about the math on it. Your common sense is good, and it's no harm/no foul.

My main experiences are with a 300 Win Mag, 270 Win, 30-06, 280 Rem, .243 Win, 30-30, 45/70, 222 Remington, .284 Win, 7mm Rem Mag, 7mm STW, 35 Whelen AI, 44 Rem Mag, 40 S&W. It's physics and consistent that when I've found signs of pressure, the larger the case, the larger the drop in charge weight needed to have that margin.

Other than the small cased handguns or rifle cartridges, I don't work with less than .5 grain changes after many years of doing this as well. Just too much minutia to chase being that precise loading each and every case, and if smaller amounts make any difference in accuracy, 30 years of targets and game haven't shown it.

A chronograph is very handy and almost necessary tool. Haven't heard you mention velocity yet. Compare your velocity to the velocity the load manuals are offering.

My load velocity vs manual velocity, in my experience, is an unbiased a sign of approaching or exceeding a max charge weight as well. Use it in conjunction with the above signs.

 

[Wrench]

A lot of reloaders think .2 or .3 makes a difference....and sometimes they're right.

If you're shooting red dot in a 380 .3 grs is potentially greater than 10%. In a 85gr case.....it's .35ish%.

If you are getting significant group changes in .3 grs with your load you're likely seeing a statistical anomaly or the world's smallest node (sarcasm).

You may try a series of groups at the load you listed and see if you repeat the bolt lift or if it was an anomaly. Pay serious attention to your seating depth as you can spike with a change and you may misread that change.

 

[TaperPin]

Background: Reloading for 40 years, but FAR FAR from expert.
Working up a load for a 338 RUM. The gun likes IMR 7828 ssc with Barnes 265 LRX. I have went overboard working on loads. Tried a ton of powders and OALs with the 265s and 280s. My best load right now is 86.8 gr of IMR 7828 ssc.

Barnes calls for a max load of 85 gr with the 265 bullet.
Nosler calls for a max load of 86.5 gr with a 265 Nosler.
Hodgen calls for a max load of 86 with a 275 bullet.

My question: The gun shot a three shot a .45 4 shot group yesterday. So yes I like that result. HOWEVER, the bolt seemed to open a little rough on one of the shots. The brass shows no signs of an over pressure situation. Nevertheless, I am thinking of dropping the load to 86.5 gr or 86.6 gr. My question is whether that is enough to really help an over pressure situation if one exists, and I am not sure that one does. I really am anxious to finish this load for this new gun. I would like to just convince my self there was no over pressure and go with 86.8, but I know I should just load a few more rounds and see if the gun is just as accurate with 2-3 tenths less powder.


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Pressure signs aren’t always easy to pin down - no one thing is a reliable gauge.

Heavy bolt lift can be seen in cases with minimally tapered sides so it’s not an automatic reliable pressure sign.

Flat primers might be soft primer cups. Rings around the firing pin indentation can be pressure or just a loose firing pin hole. Ejector marks can be pressure or normal if the brass is a brand that’s on the soft side, like Federal, win or Remington.

Measuring the case head expansion with a .0001” micrometer does show when enough pressure is there to expand the case head and eventually cause loose primers. A little expansion is ok.

Actually measuring the primer pocket with .0001” gauge pins is something that does the same thing and requires an expensive collection of gauge pins.

Checking for case head thinning that will eventually leads to a partial or full head separation is a very good check for pressure issues that can leave your rifle disabled if a case head comes off in the chamber during a hunt. Using a bent paper clip to feel for the developing case thinning, combined with visual case rings is easy and reliable. All loads will thin a little each load and excess thinning can be a reloading die/chamber/headspace issue and not pressure, but all over pressure rounds will thin cases quickly.

If a case can be reloaded 10 times and not have a loose primer pocket, not have an overly large case head expansion, or be on the verge of a case head separation, then many people feel that’s a safe load that won’t cause problems. If a load is about max I’ll mark 3 cases, measure the head and write it on the case - shoot and reload 9 times.

edit: I’ve had plenty of loads that were slightly over published max, and just as many that topped out less than what books list. If you are right at the point a case barely lasts 10 loads, a change in powder lots can put it over - it can make sense when loading big cases that burn lots of powder to have at least a few pounds of the same lot.

 

[stanginthe11s]

my opinion. Barnes is usually pretty good with their data. I have always found accuracy at or just under their max when using their bullets. I would step down to 64 and reevaluate your groups. there's no reason to push it, nothing will be gained. if you reached a point where you're in doubt, common sense says back off and be safe.

 

[35WhelenAI]

All good advice based on experience and 100 years of the reloading hobby.

OP, do you have a velocity of your load?

TaperPin, nice to see someone using case head expansion. I've done case head measurements with a micrometer as well. I look for (and stop) with .0002"-.0004" if I'm working to a max load, with .0005"-.0006" typically being the "industry" guidelines for too much.

In hunting loads, it doesn't make a difference chasing that last bit of velocity. I would say the same thing for target shooting or practice, especially since ranges are known.

Keep in mind, when primer pockets are loose, it's because the case head has expanded. I have correlated long case life, mainly primer pocket tightness, with the expansion numbers I've shared above over many rounds.

 

[TaperPin]

Keep in mind, when primer pockets are loose, it's because the case head has expanded. I have correlated long case life, mainly primer pocket tightness, with the expansion numbers I've shared above over many rounds.

That’s good to point out loose primer pockets are the result of expansion.

I have often wondered why measuring case heads isn’t more popular - a good quality .0001” mic can be picked up used for under $50. I try to show all the young reloaders in the family how it works and buy them a mic off eBay - but my guess is they don’t use it - at least they know how and have the tool. With a good mic they all do find it interesting that bullets aren’t exactly on size.

 

[35WhelenAI]

Yes, I find it interesting all the bullets aren't the same size. It's kind of a cool thing to check.

Using a micrometer to measure case head expansion is work when one can just look at a cases and talk about bolt lift like it's gospel. Honest truth.