Strange pressure, Hells canyon armory barrel problem

[Lawnboi]

Iv got a barrel that’s driving me nuts. Iv now loaded for 5 6.5cm barrels and this one is leaving me scratching my head. This barrel is from hell’s canyon armory, smith work done by him.

Early on I did a ladder with 140 hornady bullets, just to fire form the brass. I saw pressure earlier with this barrel than any other Iv loaded for. Usually around 41 of h4350 is a ways off pressure, in this barrel 40 gave me pressure. Ended up wrecking some brass being it stretched so much. Brass growth for the normal stuff was normal, maybe a bit long around .004” Anyways I loaded down, fire formed the brass then the gun sat. Accuracy with the fire forming loads was acceptable, nothing special. The pressure just left me scratching my head. This is the first creedmoor barrel Iv ever seen make pressure so low in charge. Velocity was right where I expected it, 20”, going around 2600.

Fast forward to today, I load up a ladder with some leftover 140 hybrids. 38.8-41.5 of h4350. Confirmed I wasn’t kissing the lands at Berger factory length of 2.810 and loaded them up. Brass was all bumped back two thou. Note all same lot Lapua brass. Went and shot. Got some odd results. As expected velocity tipped out at 2650.

38.5-39.5 all went normal, very little brass growth. 2500 ish fps
40-40.5 slightly stiff bolt lift, no ejector marks, brass growth +.0025
41-41.5 all normal, smooth bolt lift, no signs of pressure, brass growth back to .0015-.002.

So this leaves me scratching my head, is this something that can happen? Pressure coming and going? This barrel is driving me nuts. Is the headspace messed up? Factory brass was 1.536 to the datum, fired is 1.540 and I’m bumping to 1.538. The pieces that were still were all 1.542ish and were very tight to chamber again. I do note that this chamber allows more brass growth than any other creedmoor Iv loaded for. Most of the time im bumping to 1.536-1.537.

 

[Cahunter805]

Could be a wide variety of reasons. I would size some brass and retest 40-41.5 and see what happens.
The bore of the HCA barrel could be tighter or the reamer might not be SAAMI also.

 

[Lawnboi]

Could be a wide variety of reasons. I would size some brass and retest 40-41.5 and see what happens.
The bore of the HCA barrel could be tighter or the reamer might not be SAAMI also.

I just measured the throat and loaded a few 140 elite hunters with 41.5 grains. Brass grew .001” and zero signs of pressure. That said the throat on this thing is definetly on the long side. 2.9” and I’m .060 from jam.

So another data point, 2 more shots at 41.5 with no pressure. The 4 other creedmoors Iv loaded for all were over a grain from pressure at 41.5 and 140s. In fact it’s my go to load for my match rifle.

Just strange how 40.5 has consistently, and I’m talking over a couple dozen rounds, shown pressure by only bolt lift and primer pocket stretch, but 41 and 41.5 does not, nor does below that 40 mark.

 

[Lawnboi]

Supposed to be a saami reamer per my receipt

I also wonder if I’d see this with srp brass. The head stamp pressure I’m seeing is only around the primer cup; no ejector marks just a little shiny around the cup.

 

[drewturner]

You might check the neck diameter of a fired round vs a sized round. I doubt that would be the issue because your pressure comes and goes but I had a creedmoor that had a tight neck chamber and with brass other than Hornady i would get pressure way sooner than it should have. My fired cases and sized cases neck measurements were only .001 diff.

 

[Lawnboi]

You might check the neck diameter of a fired round vs a sized round. I doubt that would be the issue because your pressure comes and goes but I had a creedmoor that had a tight neck chamber and with brass other than Hornady i would get pressure way sooner than it should have. My fired cases and sized cases neck measurements were only .001 diff.

I did check that. A bullet slides in a fired case without difficulty.

I did more digging around and sounds like I may have either a batch of brass that is a little proud in the center, or I have a bolt face that is a hair proud in the center. Being that I am not seeing any other signs of pressure besides a little stiff bolt lift and some shine around the primer pocket I’m guessing this is the case. Im going to keep on firing. Last string of 10 loaded at 41.5 were good, had one that gave me a little shine and the bolt lift stiffness but all other were good.

I also notice that my bolt face had a cerakote on it that has now worn off everywhere but around the primer pocket, next step is to try to polish this off. The cerakote as a whole on this rifle is shit, idk what hells canyon armory did but it’s unlike my other 2 coated tikkas.

 

[Wickedpissa]

Not certain of course but sounds like you have excessive headspace. Get yourself some chamber casting alloy. Doesn’t cost much. Load dummy round in chamber push cleaning rod into muzzle make a mark where it hits. Remove both. Insert rod with tight patch a little farther than mark on rod. Approximately how much bullet shows on the dummy. Heat alloy with torch in reloading pan or something similar. Pour in chamber till full. Sets up almost instantly. Poke out with rod. Measure. Should tell you what you need. Picture is 20 Tactical that was .60 long made this happen

 

[Lawnboi]

Bringing this back up. Barrel is still doing this 300 rounds in and just got pulled. Sick of it. The thing pressures up with below book max ammo after 6-8 rounds. Dosnt act like the 8 other 6.5 creed barrel Iv loaded for now.

Since I started this thread I also have headspace guages. Headspace is fine but the back of the chamber seems a little large from the looks of the brass.

Still dosnt explain why it pressures up with heat. I’m not talking a few times either, every single time.

Sucks because the barrel shoots well, but I can’t go to a match knowing I’ll be beating on the bolt by the end of a stage.

Now Iv got a $1200 tomato stake

 

[mt100gr.]

Bringing this back up. Barrel is still doing this 300 rounds in and just got pulled. Sick of it. The thing pressures up with below book max ammo after 6-8 rounds. Dosnt act like the 8 other 6.5 creed barrel Iv loaded for now.

Since I started this thread I also have headspace guages. Headspace is fine but the back of the chamber seems a little large from the looks of the brass.

Still dosnt explain why it pressures up with heat. I’m not talking a few times either, every single time.

Sucks because the barrel shoots well, but I can’t go to a match knowing I’ll be beating on the bolt by the end of a stage.

Now Iv got a $1200 tomato stake

I sensed your dismay with that barrel in the 22CM thread. Did Mike stand behind his work at all, or did you not even bother given his lead times?

 

[Lawnboi]

I sensed your dismay with that barrel in the 22CM thread. Did Mike stand behind his work at all, or did you not even bother given his lead times?

Long story that likely deserves its own thread. This is the second barrel, first was replaced by him after finding it didn’t shoot and couldn’t zero a reasonable scope/20moa rail combo. I’m not sending him my rifle anymore, on top of that I only got partly reimbursed for shipping and a bed job on a stock that was non operational when I received it from him: I’m not being out a gun for another year

 

[willfrye027]

No carbon ring? I know some guys don’t believe in it but I had issues with my 25-284 similar to yours and for whatever reason it would develop a carbon ring fairly quickly. Pressure signs would go away when I scrubbed it out. PIA but shot well

 

[Lawnboi]

No carbon ring? I know some guys don’t believe in it but I had issues with my 25-284 similar to yours and for whatever reason it would develop a carbon ring fairly quickly. Pressure signs would go away when I scrubbed it out. PIA but shot well

No, Iv scoped it and can’t see anything abnormal. It’s only got 300 rounds on it and has been doing it since I got the barrel. It’s been cleaned as well a few times. I dunno but I know something is wrong with it. I have no use for barrel chambered saami spec that I can’t shoot light loads with for over a hand full of shots. Iv already wrecked a box of Lapua on this junk and the last barrel I wasted 3 boxes of factory ammo diagnosing issues. All for a rifle that showed up to me non operational. Im ready to take it to the dump and move on, makes me sick I spent that on a barrel.

The rifle will pressure up after half dozen shots even with really low loads. Velocity is normal to maybe a little on the low side for a creedmoor.

Sad thing is Iv heard of others with similar problems. Rokslide should know because I was under the impression I properly vetted him given what I had read here.

 

[KenLee]

Bringing this back up. Barrel is still doing this 300 rounds in and just got pulled. Sick of it. The thing pressures up with below book max ammo after 6-8 rounds. Dosnt act like the 8 other 6.5 creed barrel Iv loaded for now.

Since I started this thread I also have headspace guages. Headspace is fine but the back of the chamber seems a little large from the looks of the brass.

Still dosnt explain why it pressures up with heat. I’m not talking a few times either, every single time.

Sucks because the barrel shoots well, but I can’t go to a match knowing I’ll be beating on the bolt by the end of a stage.

Now Iv got a $1200 tomato stake

If it's a really good shooter (til it heats up) someone would want the barrel for hunting even with full disclosure...or it seems so to me. Most of my rifles never get 6 shots in an outing, much less in a short time period.

 

[Lawnboi]

If it's a really good shooter (til it heats up) someone would want the barrel for hunting even with full disclosure...or it seems so to me. Most of my rifles never get 6 shots in an outing, much less in a short time period.

I couldn’t find it in me to even give a barrel away that I thought could be dangerous unfortunately

Wish I could figure out what was wrong with it though.

 

[KenLee]

I couldn’t find it in me to even give a barrel away that I thought could be dangerous unfortunately

Wish I could figure out what was wrong with it though.

I'm a sucker for a good shooter and would roll the dice and hunt with it. Full disclosure, I'm only 5 years away from where the longest living male in my family tree kicked off at 60. Not a huge gamble at this point.

 

[Dos XX]

Take or send it to another gunsmith. A good one. Why would anyone cerakote a bolt face? Did I read that wrong?

 

[Lawnboi]

Take or send it to another gunsmith. A good one. Why would anyone cerakote a bolt face? Did I read that wrong?

I don’t have a problem with the bolt face being coated. The whole action appears to have been coated twice though which didn’t help cycling.

But I don’t think this is a chamber problem, I think it’s a barrel problem. It’s a carbon barrel so who knows. The carbon is uneven in places and has almost a spine along one edge. I have no clue if it could be a stress problem, air pocket problem or what. It’s strange. I have loaded thousands of 6.5cm rounds for a bunch of barrels, from a number of smiths. This one has me scratching my head.

Same ammo I can get to go from safe for a few shots or even more if I shoot them very slow. Once it gets hot I get ejector swipe and stiff bolt lift. This is ammo that is below book max… in a creedmoor… which isn’t even close to pushing it.

I’m not spending any more money on the barrel.

 

[Gasman]

Before totally giving up on the barrel, you might want to try trimming a few pieces of brass shorter than you normally would and then loading them up. If the resulting rounds don't have pressure issues, it probably means that the chamber in this rifle has a short neck - the necks of standard length brass are getting pinched (kind of like crimping) when they're forced into the chamber, leading to high pressures. This isn't something that can be detected with headspace gauges.

The heat thing I don't get at all.

 

[Lawnboi]

Before totally giving up on the barrel, you might want to try trimming a few pieces of brass shorter than you normally would and then loading them up. If the resulting rounds don't have pressure issues, it probably means that the chamber in this rifle has a short neck - the necks of standard length brass are getting pinched (kind of like crimping) when they're forced into the chamber, leading to high pressures. This isn't something that can be detected with headspace gauges.

The heat thing I don't get at all.

That is something I checked with the bore scope as well.

It makes no sense to me either. I can’t even load low enough to not cause pressure, but only after 6-10 shots. No idea what is going on.

 

[prm]

I had some brass with a slightly long neck that was getting squeezed at the front of chamber when closing bolt. Definitely jacked the pressure up.
edit: just saw Gasman’s post. Same. How that could relate to temp I have no idea, nor any other suggestions. Odd.