Help me figure this out. Bulged case head.

[happyfast79]

I just swapped out a factory 20 inch rifle gas psa 6.5 Creedmoor barrel for a 22 inch +2 gas 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

 

[Alabusa]

Out of battery possible?

 

[hlee]

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

Well, that looks like insipient case head separation. Combined with ‘primer leakage’ and a “lost primer” I’d say you have found and exceeded max pressure. Have you measured how much growth in case length from unfired to fired? That might give you some info on the chamber. But again, blown and lost primers are generally good sighs of over pressure.

 

[happyfast79]

Out of battery possible?

They all have the ring , just some ypu could just see and as the loads got hotter the ring started to protrude, the bolt is locked into the barrel extension.

 

[msgriff]

What bolt and was it headspaced?

 

[happyfast79]

Well, that looks like insipient case head separation. Combined with ‘primer leakage’ and a “lost primer” I’d say you have found and exceeded max pressure. Have you measured how much growth in case length from unfired to fired? That might give you some info on the chamber. But again, blown and lost primers are generally good sighs of over pressure.

The case head separation that I have seen. in the past doesnt expand out like these did. That ring is .010 bigger than the rest of the case. Isn't that part of the case supposed to be in the chamber? I'll do some more measurements and get back with you on the length.

 

[happyfast79]

What bolt and was it headspaced?

It's the factory psa ( tool craft high pressure dual ejector bolt that came in the rifle from psa)

 

[hlee]

The case head separation that I have seen. in the past doesnt expand out like these did. That ring is .010 bigger than the rest of the case. Isn't that part of the case supposed to be in the chamber? I'll do some more measurements and get back with you on the length.

Check the chamber specs in this thread…

6.5 Creed & 6.5 PRC

Can factory 6.5 Creed be fired in a 6.5 PRC to obtain brass? What about headspace? Will the brass be usable or is this too big a stretch?

www.snipershide.com

 

[happyfast79]

Check the chamber specs in this thread…

6.5 Creed & 6.5 PRC

Can factory 6.5 Creed be fired in a 6.5 PRC to obtain brass? What about headspace? Will the brass be usable or is this too big a stretch?

www.snipershide.com

Thanks! I will

 

[happyfast79]

So my case diameters are in spec except for that ring and it is .474-.481 on the hotter loads but .470 right in front of that ring. Case length on virgin brass is 1.909 and most of the fired stuff shrunk to 1.899 , with a few odd ball ones being 1.894 and 1.918

 

[Molon]

Out of battery possible?

No.

....

 

[hlee]

So my case diameters are in spec except for that ring and it is .474-.481 on the hotter loads but .470 right in front of that ring. Case length on virgin brass is 1.909 and most of the fired stuff shrunk to 1.899 , with a few odd ball ones being 1.894 and 1.918

The overall length of the fired case is less important than the shoulder measurement- from the back of the case to the 0.400" measurement on the shoulder. The OAL may shrink as brass is "used" to blow out the shoulder upon firing.

 

[Molon]

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 . . .

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.

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.

...

 

[happyfast79]

The overall length of the fired case is less important than the shoulder measurement- from the back of the case to the 0.400" measurement on the shoulder. The OAL may shrink as brass is "used" to blow out the shoulder upon firing.

Thats

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 recess of the barrel extension.

...

Thanks for the pictures, I wasn't sure if there was that much unsupported case in a AR. So maybe I need to abandon reloader 17 in this cartridge. I thought I started pretty low on the charge and even on the first loads u could see a line in that spot. And barrel didn't seem to shoot well with any of those loads. Any chance on my brass being soft?

 

[Aftermath]

HAHAHAHAHAHAHAHAHA!!!!!

OP: I have shit happening and I don't have a fucking clue what is going on, please help.
OP: You guys don't know shit.

 

[hafejd30]

I give you the belted Creedmoor!!

 

[BuildingConceptsllc]

Thats

Thanks for the pictures, I wasn't sure if there was that much unsupported case in a AR. So maybe I need to abandon reloader 17 in this cartridge. I thought I started pretty low on the charge and even on the first loads u could see a line in that spot. And barrel didn't seem to shoot well with any of those loads. Any chance on my brass being soft?

Doubtful. I'd say there's just a really good chance that you are way over pressure , like @Molon just told you.

 

[TheOfficeT-Rex]

If it's not pissing hot, it's not Hide Load Data...

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

Hornady book lists 41.3 as max with that combo. FYSA.

 

[happyfast79]

HAHAHAHAHAHAHAHAHA!!!!!

OP: I have shit happening and I don't have a fucking clue what is going on, please help.
OP: You guys don't know shit.

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.

 

[happyfast79]

If it's not pissing hot, it's not Hide Load Data...




Hornady book lists 41.3 as max with that combo. FYSA.

I need to get a newer book lol

 

[mtrmn]

From my observance over the years, anytime Molon gets involved you're fixing to learn some shit. Listen to Molon. That is all.

 

[happyfast79]

From my observance over the years, anytime Molon gets involved you're fixing to learn some shit. Listen to Molon. That is all.

Good to know. Thanks for the heads up

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.

I'll back way down and see how it does. Thanks for the info and pictures

 

[happyfast79]

If it's not pissing hot, it's not Hide Load Data...




Hornady book lists 41.3 as max with that combo. FYSA.

This is the load data I was going off. I looked at my loads and I started at 39 and top load was 42 grains of rl17. Happen to have a picture of the page in the newer manual?

 

[TheOfficeT-Rex]

I'm lazy, have a google image. This is tenth book, there's a new one out.

 

[happyfast79]

View attachment 8037039

I'm lazy, have a google image. This is tenth book, there's a new one out.

Thank you! I'm lucky my newest Hornady manual even has the 6.5 manbun in it lol

 

[BuildingConceptsllc]

From my observance over the years, anytime Molon gets involved you're fixing to learn some shit. Listen to Molon. That is all.

That's a fact. Molon not only has the experience with AR's in particular but he also had the equipment to measure about anything and has probably already tested it with documentation.

 

[rpoL98]

View attachment 8037039

I'm lazy, have a google image. This is tenth book, there's a new one out.

11th edition data is same for RL17. p.338.

 

[happyfast79]

11th edition data is same for RL17. p.338.

Thanks for checking. Any of you guys using Rl17 in a 6.5 gas gun with good results? I'm gonna try to grab some 6.5 staball and try it too

 

[rpoL98]

Thanks for checking. Any of you guys using Rl17 in a 6.5 gas gun with good results? I'm gonna try to grab some 6.5 staball and try it too

you should get a current book, first. JMHO.

but admittedly, I'll be the first to say, I don't know shet.

 

[GreenGO Juan]

^

You are literally blowing out primers and bulging the case...

There is more information in those manuals than just charge weights. You are lucky that budge did not blow out and ruin your day.

You were literally right on the edge of blowing shit up... and seem completely aloof of it.

Edit- like seating depth. Which you have past the recommended coal.

Or trim lenght

Who knows what you are doing to cause that dangerously high pressure.

 

[happyfast79]

View attachment 8037111
^

You are literally blowing out primers and bulging the case... View attachment 8037117

There is more information in those manuals than just charge weights. You are lucky that budge did not blow out and ruin your day.

You were literally right on the edge of blowing shit up... and seem completely aloof of it.

Edit- like seating depth. Which you have past the recommended coal. View attachment 8037126
Or trim lenght
View attachment 8037127

Who knows what you are doing to cause that dangerously high pressure.

So that bullet hits the lands at 2.915 , wouldn't increasing coal lower pressure? If not please explain

 

[happyfast79]

And I'll be the first to admit that I made a mistake.

 

[TheOfficeT-Rex]

Increasing OAL isn't going to save you from dropping too much powder in the case. Go back to book starting loads and start over.

 

[happyfast79]

Increasing OAL isn't going to save you from dropping too much powder in the case. Go back to book starting loads and start over.

That's the plan. Thanks. I was just trying to figure out his comment about me having the bullet seated out further than the book says Contributing to higher pressure.

 

[TheOfficeT-Rex]

That's the plan. Thanks. I was just trying to figure out his comment about me having the bullet seated out further than the book says Contributing to higher pressure.

He's telling you to RTFM and re-verify all your steps.

 

[happyfast79]

He's telling you to RTFM and re-verify all your steps.

Yeah I got some up to date load data to try this time. I'll be starting on the low end and work my way up, and maybe try a different powder

 

[happyfast79]

Thank you all for the info

 

[GreenGO Juan]

So that bullet hits the lands at 2.915 , wouldn't increasing coal lower pressure? If not please explain

Did you read and comprehend that section of manual? How seating depth affects pressure?

Closer to the lands.
A) straight Fucks
B) raises pressure
C) lowers pressure
D) she loves the D
E)depends
Example below.

 

[happyfast79]

Did you read and comprehend that section of manual? How seating depth affects pressure?

Closer to the lands.
A) straight Fucks
B) raises pressure
C) lowers pressure
D) she loves the D
E)depends
Example below.

View attachment 8037198


View attachment 8037199

So me extending the bullet out of the case .025 and still being .090 off the rifling should decrease chamber pressure.

 

[GreenGO Juan]

So me extending the bullet out of the case .025 and still being .090 off the rifling should decrease chamber pressure.

You are seeing extreme pressure signs and you think your process is lowering the chamber pressure?

Good luck!

 

[B y r o n]

This is the load data I was going off. I looked at my loads and I started at 39 and top load was 42 grains of rl17. Happen to have a picture of the page in the newer manual?

That load data was for 140 gr bullet and you were using 143 gr.

 

[happyfast79]

That load data was for 140 gr bullet and you were using 143 gr.

Yes and have been given the load data in this thread to start again with. 140 gr bullet max was 42gr and the 143 gr max was 41.3 gr.

You are seeing extreme pressure signs and you think your process is lowering the chamber pressure?

Good luck!

I'm asking about in theory, there is no doubt that I had over pressure, that horse has already been beat enough. My question on this is if someone with a perfectly safe pressure load (not mine that wasnt) , seats the bullet out of the case .025 ( so case capacity is increased by the bullet taking up less powder space) and that bullet is still .090 from the rifling ( not jammed). In theory would drop chamber pressure? I'm looking to learn here, so give me some meaningful feed back.

 

[RTH1800]

Stop reloading ammunition NOW! You are not suited for it.

 

[Precision Underground]

The 6.5 RL17 load we use in our gas gun is a hot 44.4.……But that’s with a 123 ELD!

 

[happyfast79]

Stop reloading ammunition NOW! You are not suited for it.

Deep thoughts lol

 

[happyfast79]

The 6.5 RL17 load we use in our gas gun is a hot 44.4.……But that’s with a 123 ELD!

OK. Good to know it works. I'll start another lower and work my way up. Thanks for the reply

 

[RTH1800]

Deep thoughts lol

More so than you think.

 

[BCP]

and one of those lost a primer and it jammed it's self in the bolt cam pin bore and locked the gun up

You're over pressure, congrats.

 

[lash]

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.

 

[Molon]

So me extending the bullet out of the case .025 and still being .090 off the rifling should decrease chamber pressure.

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

...