Help me figure this out. Bulged case head.

[Precision Underground]

What should decrease the chamber pressure is starting at the minimum powder charge listed in the manual and working up from there.

...

I admittedly don’t do this and prob should. But….. I would have stopped at the first sign of pressure rather than continuing to the belted creedmoor lol. So one lesson is to start at the low charge. But another good lesson is to know the signs of pressure and believe the brass. If you’re seeing your primers pierce and your brass bulge, forget what the book says and stop.

 

[happyfast79]

What should decrease the chamber pressure is starting at the minimum powder charge listed in the manual and working up from there.

...

That's the plan

 

[happyfast79]

I think that the OP wants to learn. He’s recognized and admitted now that he was over pressure. Here’s what has been discussed so far:

1. He should step back for a little bit to read his reloading manual’s first chapters. The ones not just listing loads. The ones that give a quick lesson about safe practices and the important basics to follow.

2. As was hinted at but not detailed; given all things the same, a heavier bullet with a charge used for lighter bullets will create more pressure. Sometimes too much pressure, becoming dangerous.

3. A blown primer is most often a sign of severe pressure.

4. When there is metal deformation that is noticeable to the eye, you need to stop immediately and evaluate what you did, before you hurt yourself.

5. It is hard learning some of these things if you’ve not had a mentor or have any experience in the area. That is why a good bout of reading and measuring things is very, I mean very, important. Until you actually know what you are doing, and then always throughout the process of any hand loading always be measuring dimensions of things.

6. If you don’t know which things, why, when or how. Do more reading and ask questions until you do.

There’s more, much more, but I think the point has been made.

I was stupid. Your post was informative and helpful.

 

[tomme boy]

GUYS! There are 2 things going on here and it is manufacturing f ups!

1, the coned breech is too deep. They cut it wrong. This leaves the case head unsupported.
2. Starline brass. Starline has a problem of the web being too low in the case. This will be fine in a barrel that does not use a coned breech face. All AR platform do. But when combined with a coned breech it can be very bad.

So you get a case that has a low web and is not supported in the chamber. Then you get belted brass on a safe load. It is not over pressure unsafe loads. They would do this on a barrel that is spec. This one is NOT.

The OP needs to contact who ever made the barrel and ask for their money back And to call starline and tell them to stop making garbage brass. This comes up all the time using brass from them in the 350 Legend.

 

[hlee]

GUYS! There are 2 things going on here and it is manufacturing f ups!

1, the coned breech is too deep. They cut it wrong. This leaves the case head unsupported.
2. Starline brass. Starline has a problem of the web being too low in the case. This will be fine in a barrel that does not use a coned breech face. All AR platform do. But when combined with a coned breech it can be very bad.

So you get a case that has a low web and is not supported in the chamber. Then you get belted brass on a safe load. It is not over pressure unsafe loads. They would do this on a barrel that is spec. This one is NOT.

The OP needs to contact who ever made the barrel and ask for their money back And to call starline and tell them to stop making garbage brass. This comes up all the time using brass from them in the 350 Legend.

Maybe, but blown primers say otherwise…

 

[BuildingConceptsllc]

GUYS! There are 2 things going on here and it is manufacturing f ups!

1, the coned breech is too deep. They cut it wrong. This leaves the case head unsupported.
2. Starline brass. Starline has a problem of the web being too low in the case. This will be fine in a barrel that does not use a coned breech face. All AR platform do. But when combined with a coned breech it can be very bad.

So you get a case that has a low web and is not supported in the chamber. Then you get belted brass on a safe load. It is not over pressure unsafe loads. They would do this on a barrel that is spec. This one is NOT.

The OP needs to contact who ever made the barrel and ask for their money back And to call starline and tell them to stop making garbage brass. This comes up all the time using brass from them in the 350 Legend.

I've not shot starline in an AR with 6.5cm , but I have shot A LOT of it in a bolt. I've also shot it in a 223 AR, and with some hot loads too , I've never had any issue with starline brass and found it to be very good. I shoot that and lapua only so that's what I'm comparing it to. The chamber may well have some issue, but that case looks a whole lot like the lapua case that came out of my AR with the Berger Factory ammo that was ridiculously too hot. Looks exactly like the one Molon posted here, and that's Lapua brass so, I'm not sure how you came up with that nor if you're wrong but I think more info is required before making any declarative statements about the brass

 

[tomme boy]

Maybe, but blown primers say otherwise…

It would still have happened sooner or later. You can not over look the f'ed up barrel and brass. I have seen this happen with starting book loads. The coned breech is cut wrong and the brass is shit

 

[tomme boy]

I've not shot starline in an AR with 6.5cm , but I have shot A LOT of it in a bolt. I've also shot it in a 223 AR, and with some hot loads too , I've never had any issue with starline brass and found it to be very good. I shoot that and lapua only so that's what I'm comparing it to. The chamber may well have some issue, but that case looks a whole lot like the lapua case that came out of my AR with the Berger Factory ammo that was ridiculously too hot. Looks exactly like the one Molon posted here, and that's Lapua brass so, I'm not sure how you came up with that nor if you're wrong but I think more info is required before making any declarative statements about the brass

Do you even know what a coned breech is? measure the brass and then comment. Or section the brass. I have. Not all starline brass has the problem but some does and it shows here.

 

[BuildingConceptsllc]

Do you even know what a coned breech is? measure the brass and then comment. Or section the brass. I have. Not all starline brass has the problem but some does and it shows here.

I'm confused, you want me to measure his brass? Have you measured his brass? Is there something I don't know about you two here?

 

[tomme boy]

If you have multiple makers brass measure the depth of the web and compare. Some brass I have measured had a 0.01" lower web. That is enough to make this happen. Hornady had this happening with factory ammo a couple years ago because of their brass having a low web and being shot in an AR.

He may have had high pressures but it still does not help that the barrel is f'ed up and also the brass. The brass and ammo manufacturers are relying on the gun makers to not have a f'ed up chamber. And the gun makers are relying on the ammo makers to have properly made brass. Then when both f up this shit happens.

 

[BuildingConceptsllc]

If you have multiple makers brass measure the depth of the web and compare. Some brass I have measured had a 0.01" lower web. That is enough to make this happen. Hornady had this happening with factory ammo a couple years ago because of their brass having a low web and being shot in an AR.

He may have had high pressures but it still does not help that the barrel is f'ed up and also the brass. The brass and ammo manufacturers are relying on the gun makers to not have a f'ed up chamber. And the gun makers are relying on the ammo makers to have properly made brass. Then when both f up this shit happens.

Ok, I see what you were saying now. I will check that out and see. I have a micro I can get a good measurement with

 

[Robert4]

Try a dummy round just like the one in question here. Feed it from the magazine by letting the BCG snap closed. See if the bullet is driven deeper in the case. A problem with the feed ramps combined with not enough bullet tension could drive the bullet enough deeper into the case to cause problems.

 

[Pirate-69]

Just for kicks, I ran the OP's load through QuickLoad at 70F.
22" barrel
42 grains of RL17
143 gr eldx
2.825 COAL

QL predicts a chamber pressure of 60,991 psi. Max is 63,091 psi. Velocity of 2789 fps.
If bullet is actually into the lands, shot start pressure could increase by as much as 7,200 psi. 70291 psi.

There was a question on neck tension earlier. If bullet was driven back 0.1" during chambering, the pressure would exceed 65k psi.

May get flamed but only thing I can contribute.

 

[happyfast79]

Update. Shot factory federal 123gr American eagle and did a full work up from a minimum load in the Hornady manual with 6.5 staball. Federal showed a less pronounced ring around the brass and mild book load started showing a more pronounced ring starting at 39.7 gr of 6.5 staball with 143 eldx at 2.800 with win LR primer.

 

[msgriff]

Update. Shot factory federal 123gr American eagle and did a full work up from a minimum load in the Hornady manual with 6.5 staball. Federal showed a less pronounced ring around the brass and mild book load started showing a more pronounced ring starting at 39.7 gr of 6.5 staball with 143 eldx at 2.800 with win LR primer.

One year later, talk about "back burner". It's probably just the angle of the pic, but that feed cone looks eccentric to the bore.

 

[happyfast79]

One year later, talk about "back burner". It's probably just the angle of the pic, but that feed cone looks eccentric to the bore.

Yeah definitely back burner. Cone looks to be concentric to the bore

 

[LRRPF52]

FWIW, I don’t use RL-17 in 6.5-08 gas guns. It’s great in bolt guns for velocity, but I think the pressure curve is too long.

You might be able to get away with it using ELGS, but it seems to be too slow-burning for RLGS gas port locations.

It was known for being the speed demon back in the 2000s for those of us who started shooting .260 Rem then, but for gas guns, it seemed to be too much.

I think it’s the powder that sent my BCG and buffer slamming back into my rifle RET hard as well.

I settled on 130gr Bergers and didn’t look back. Laser-flat, beautiful wind-cutting, accurate.

I think I was using N540 and H4350 the most. It’s been a while.

 

[happyfast79]

FWIW, I don’t use RL-17 in 6.5-08 gas guns. It’s great in bolt guns for velocity, but I think the pressure curve is too long.

You might be able to get away with it using ELGS, but it seems to be too slow-burning for RLGS gas port locations.

It was known for being the speed demon back in the 2000s for those of us who started shooting .260 Rem then, but for gas guns, it seemed to be too much.

I think it’s the powder that sent my BCG and buffer slamming back into my rifle RET hard as well.

I settled on 130gr Bergers and didn’t look back. Laser-flat, beautiful wind-cutting, accurate.

I think I was using N540 and H4350 the most. It’s been a while.

Thanks for the info, I just happen to have it on hand as RL 17 is what I use in my 20 inch 375 ruger and get great velocities. I ended up getting a few pounds of 6.5 stabal to try out.

I need to pick up some lighter bullets and some h4350, I've got 140 eldm and 143 eldx bullets that I run in my 6.5x55 tikka.


Thanks again for the info

 

[BuildingConceptsllc]

FWIW, I don’t use RL-17 in 6.5-08 gas guns. It’s great in bolt guns for velocity, but I think the pressure curve is too long.

You might be able to get away with it using ELGS, but it seems to be too slow-burning for RLGS gas port locations.

It was known for being the speed demon back in the 2000s for those of us who started shooting .260 Rem then, but for gas guns, it seemed to be too much.

I think it’s the powder that sent my BCG and buffer slamming back into my rifle RET hard as well.

I settled on 130gr Bergers and didn’t look back. Laser-flat, beautiful wind-cutting, accurate.

I think I was using N540 and H4350 the most. It’s been a while.

I love that bullet. I shoot it in my bolt gun and it's fantastic. Super accurate and with h4350 it's just an easy button.

 

[sinister]

Well, that looks like insipient case head separation ... blown and lost primers are generally good sighs of over pressure.

Those are what is known as "clues."

Your loads are over-pressure in that barrel. The "ring" that you're seeing is the brass flowing into the recess of the barrel extension.

Lol not quite, just making sure I've got my bases covered. I've never used starline rifle brass before so I just wanted to make sure. I'm used to seeing pressure signs on the back of the case at the ejector, so this one threw me for a loop.

I just swapped out a factory 20 inch rifle gas psa 6.5 Creedmoor barrel for a 22 inch +2 gas Odin works tactical match barrel. This was the first firing on star line brass, had some strange rings around the base of the case on lighter loads, then some primers were leaking gas around them on a few pieces of the next few loads.

The hottest load I checked had a.010 bulge around the back of the case ( belted magnum ) and one of those lost a primer and it jammed it's self in the bolt cam pin bore and locked the gun up.. needless to say I stopped there.

Shot some factory 123 grain federal stuff and brass looked fine, shot some of these same loads with the same brass out of the factory barrel and they looked fine. I did not run a set of headspace gages through this rifle after the barrel change. What are you guys thoughts? Thanks in advance.

Loads were 39-43 grains of rl17 with 143 eldx set at 2.825 coal. Win primers

Good of you to ask for advice.

I'm not sure I'd blame the guy who cut your chamber and bevel. Your factory rounds didn't show any brass flow but your handloads seem to show you're really pushing the boundaries of the limits of physics, chemistry - thermodynamics, and metallurgy.

Lucky for you your brass is doing its job as a pressure vessel while the brass is elastic and stretching to its limits. Your primer pockets are just giving up the ghost. The +2 gas system is preventing the bolt from turning and extracting while your cases are still obturated at excess pressure. Check your bolt face for flame cutting and cratering around the primer pocket periphery.

How many rounds have you fired exceeding manufacturer load data? I've done it if I've asked from guys I know or have shot with, but just fishing until failure is a bold strategy.

 

[happyfast79]

View attachment 8340755



Good of you to ask for advice.

I'm not sure I'd blame the guy who cut your chamber and bevel. Your factory rounds didn't show any brass flow but your handloads seem to show you're really pushing the boundaries of the limits of physics, chemistry - thermodynamics, and metallurgy.

Lucky for you your brass is doing its job as a pressure vessel while the brass is elastic and stretching to its limits. Your primer pockets are just giving up the ghost. The +2 gas system is preventing the bolt from turning and extracting while your cases are still obturated at excess pressure. Check your bolt face for flame cutting and cratering around the primer pocket periphery.

How many rounds have you fired exceeding manufacturer load data? I've done it if I've asked from guys I know or have shot with, but just fishing until failure is a bold strategy.

Factory federal IS showing the same thing

 

[sinister]

Factory federal IS showing the same thing

Shot some factory 123 grain federal stuff and brass looked fine ...

I must have missed something.

 

[happyfast79]

Factory federal IS showing the same thing

I must have missed something.

Must have missed my update post a year latter lol ( it got put on back burner) It's not as pronounced as the first time but it's there with factory federal ammo. Maybe I didn't catch it on the first factory stuff that I shot through it a year ago

 

[sinister]

OK, I see your post in #64 now. I see a ring, but not the raised belted magnum ring.

Yes, the bevel at the bottom of your chamber is excessive for your Reloder 17 loads.

You are being saved from a rifle kaboom only because the brass at the bottom of the case hasn't ruptured while it was being forced to the limit of its elastic strength, forming that raised belted magnum style ring.

If the case isn't supported the brass will simply flow until it ruptures at the web. Example (excessive headspace in a bolt rifle in this particular instance):