6.5 PRC Over pressure with H1000 and 156 Bergers

[Old Infantry Guy]

According to Hodgdon the maximum load for 156 grain Bergers is 55.0 grains of H1000 powder. If their calculations were based on Hornady brass, the maximum load for ADG would be even less.

 

[WYO300RUM]

Yes ADG brass takes less powder. He was at dangerous pressure level. Drop it back down and try again. RL26 and N560 N565 work great in prc and will give him better velocity's at safe pressure.

I use 55.0 gr. RL26. ADG brass . Fed. 210 Match. 156 Berger. Ave. 2932 fps. 24 in.barrel. Bugholes. Pressure at 57.0 grs.. H1000 didn't work as well.
I got pressure at 58.0 grs. H1000.

 

[Rflshootr]

Sometimes people also overlook the maximum case length and forget to trim. This can cause an over pressure problem as well. May or may not be a contributing factor in this instance.

 

[vancewalker007]

Aloha All

Just wanted to post this here to see if anyone has anything similar happen to them. With this powder/bullet combo. Thanks in advance!

Have a buddy who hads a 6.5 PRC giving him issues on a hunt right now.

Here's his load specs:
New adg brass,
F215M
60gn h1000,
Berger 156 eol,
coal 3.0735,
cbto 2.360 = 15 thou off the lands

He told me he spoke to berger to get chg weights for H1000 & this cartridge/bullet combo. He was given 54.5 start 60.4 Max. He did note that they wouldn't give him brass brand they were using.

He did load work up from 56-60.5, 60.5 had very slight bolt lift resistance, Not heavy etc! Settled on 60 gr load less than .5 groups.

Below is what he had from LR for velocity. Until yesterday he had shot roughly 30 rounds with no pressure signs etc. Temps here are mid to high 80's

So he checks zero yesterday before today's hunt and first 3 shots all blown primers heavy bolt lift. He's scratching his head and bummed because he only took 20 rounds of 143's with him which he's already shot 10 lol.

Only thing that comes to mind is if the ADG Brass has a different volume than what berger was using (I'm thinking hornady?) Therefore the ADG Max is less than what berger is using. BUT...he worked up loads and none showed high pressure signs.

Idk what ppl seeing for velocity with this bullet but I told him that what he's getting is up there. But idk much about the PRC. I have a 6.5x284 n only doing 2950 with 130's.

He's got meat in the cooler so I told him I'd try and ask if anyone has ideas on the forums.

Sorry, his rifle is built on a tikka action. Started out as 300 Win mag. Had gunsmith rebarrel it with a proof sendero 7.5 twist 26" Put it in a woox exacts stock l believe.

If some of those cases didn't size correctly around the web you can get pressure that will pop a primer. The case has no space to expand and wham-o. With this cartridge you really need to get that web area down to .532in or less. I've found even .5325 can cause pressure spikes. If this friend is running tight against his rifles max then he is putting a lot of pressure/work on his cases which can also make them hard to resize. I've found that cases that have experienced pressure in my rifle will not size down in the web area no matter what I do. This can show with a mark from an ejector on the base or a heavy swipe and tight extraction bolt lift.

I have started carefully checking each case I resize in my rifle as I go. I am using the Hornady Match Grade FL die with .294 first pass and .290 final bushings. If a case closes even slightly tight and I cannot get the dimension down I toss it. If you have your die set right resized cases should close almost as easy as fresh unfired cases. Also, against Dogma I started bumping my shoulder 4-5 thou instead of 2 on this cartridge. This seems the help get all the case dimension smaller with the die I am using. It took some careful measuring and screwing the die in and out some but it has paid off in getting cases I was ready to toss back into working shape.

BTW - My rifle maxed out at 58.6gr of H1000 with the 156 EOL, Hornady cases, CCI BR2s. I have found that mag primers can raise pressure a little in short mags as well. I quit using them back in my 270/300 WSM days. My rifle is a Defiance Deviant Ultra-light XM, 26in Proof Sendero with more chamber lead than SAAMI so at 15 off the 156 EOL base is a hair above the neck shoulder junction. So I have a lot of case space for internal ballistics. He may want to more carefully re-do his max load check and be more critical about where he feels pressure. Like calling any resistance on the bolt a pressure sign. Your better off dropping a few FPS and putting less pressure on cases in the long run.

 

[GBWS]

Aloha All

Just wanted to thank everyone who took the time to respond here. Greatly appreciate it!!! I'll work with him when he gets back from his hunt.

Thanks again!

Aloha

Dom

 

[Painless300]

If some of those cases didn't size correctly around the web you can get pressure that will pop a primer. The case has no space to expand and wham-o. With this cartridge you really need to get that web area down to .532in or less. I've found even .5325 can cause pressure spikes. If this friend is running tight against his rifles max then he is putting a lot of pressure/work on his cases which can also make them hard to resize. I've found that cases that have experienced pressure in my rifle will not size down in the web area no matter what I do. This can show with a mark from an ejector on the base or a heavy swipe and tight extraction bolt lift.

I have started carefully checking each case I resize in my rifle as I go. I am using the Hornady Match Grade FL die with .294 first pass and .290 final bushings. If a case closes even slightly tight and I cannot get the dimension down I toss it. If you have your die set right resized cases should close almost as easy as fresh unfired cases. Also, against Dogma I started bumping my shoulder 4-5 thou instead of 2 on this cartridge. This seems the help get all the case dimension smaller with the die I am using. It took some careful measuring and screwing the die in and out some but it has paid off in getting cases I was ready to toss back into working shape.

BTW - My rifle maxed out at 58.6gr of H1000 with the 156 EOL, Hornady cases, CCI BR2s. I have found that mag primers can raise pressure a little in short mags as well. I quit using them back in my 270/300 WSM days. My rifle is a Defiance Deviant Ultra-light XM, 26in Proof Sendero with more chamber lead than SAAMI so at 15 off the 156 EOL base is a hair above the neck shoulder junction. So I have a lot of case space for internal ballistics. He may want to more carefully re-do his max load check and be more critical about where he feels pressure. Like calling any resistance on the bolt a pressure sign. Your better off dropping a few FPS and putting less pressure on cases in the long run.

Very good info here. My max was 59.5 using Hornady brass and found a very good node at 58.6 with the 156's. But, everyone in a while I was get heavy bolt lift and ejector swipe, primers always look fine. I know I am probably running a little hot but I thought it was strange to get heavy lift 1 out of 20 rounds. Maybe exactly what you are saying here. I'll also trim the next go around. Hopefully this will solve my issue or I just need to go down to the lower node!
For clarification - Running a 22" Proof at 2915MV ES 8-12 with 58.6 H1000 and 156 Berger's got 275 rounds down the barrel.
By the way they are bad medicine on my GA whitetails! Furthest shot out to 400 yds.

 

[Hunterjones]

So, this has to do with ADG brass but not in the PRC. When I got my first 28 Nosler I bought 200 Nosler Cases. Brass life was very poor on some cases. Once I found "the load" I decided to switch to ADG Brass when some became available. The ADG cases average 10-15 grains LIGHTER but case capacity is almost IDENTICAL between the Nosler and ADG brass. ANYWAY, I needed to add 2.5 more grains of RE33 to the ADG Brass to equal the velocity and accuracy of the Nosler brass.
Turns out the necks on the Nosler brass are .002-.003 thicker than the ADG Brass

 

[vancewalker007]

Very good info here. My max was 59.5 using Hornady brass and found a very good node at 58.6 with the 156's. But, everyone in a while I was get heavy bolt lift and ejector swipe, primers always look fine. I know I am probably running a little hot but I thought it was strange to get heavy lift 1 out of 20 rounds. Maybe exactly what you are saying here. I'll also trim the next go around. Hopefully this will solve my issue or I just need to go down to the lower node!
For clarification - Running a 22" Proof at 2915MV ES 8-12 with 58.6 H1000 and 156 Berger's got 275 rounds down the barrel.
By the way they are bad medicine on my GA whitetails! Furthest shot out to 400 yds.

Yeah, those 156's will drop deer in their tracks. We've killed 4 Coues bucks with it over last 3 years. My 26in barrel is making 3040fps with 58.2gr H1000. Getting ready to try them on antelope in Africa.

 

[Calhntr]

Different brass=different volume, no two same cartridge chambers are the same, no two same caliber barrels are the same, reloading manuals provide a safe starting point but all loads must be worked up, what they've determined as max. may not be safe for your rifle, or sometimes not the max. load for your rifle, and....some barrels shoot faster or slower, same cartridge, same barrel length, I have 4 factory .270 winchesters, 2-model 70's, 1-Browning, 1-Ruger, My fastest is a Win. M70 handloaded with no pressure signs makes an avg. 3292fps. In 24" , H4831SC pushing a 130grain Hornady GMX .065" off the lands. Can't use this load in the other Win. M70 or other rifles. And.....my handload is just under 1 MOA. For 5 rounds@100yds. And....beats the Accuracy and velocity! of Hornadys factory loaded Superformance 130 gr. GMX( 2"+ groups, sad ) in the same Win. Mod 70.

 

[GBWS]

Thank you gentlemen, really appreciate your responses!!

 

[Buxndiverdux]

60 grains of H1000 and the 156 Berger in a 6.5 PRC is HOT...

 

[GBWS]

Sure seems that way bud. Just weird he shot it a bunch before showing pressure. Anyhow, I told him when he gets back to back it down and work on his 57.5 gr load. It shot great there too.

Thanks!

 

[Deleted member 107796]

60gn H1000 exceeds the data for Barnes 130gn (58.1gn), Hornady 143gn (59.0), and Hornady 147gn (57.4).
Like the song goes, "they're hot, hot hot!"

 

[Eric Musgrove]

Good Morning,
Last year I called Berger and they told me the same info, we discussed seating depths as well. I don't have my notes in front of me at the moment. I loaded up the same loads with Hornady brass and had heavy bolt lift at 60 grs of H1000, I believe it was around 80-85F so I stopped and later pulled the rest. I assumed this was because my X-bolt pro has a mag and I was at max length for the mag and couldn't seat them longer. I settled on a load of 59.5 grs I will get my notes later and check but I believe it was 2990 fps(24in barrel) and accuracy was 1/2 moa at 200 yards. I was able to get some 143 ELDX bullets and I am currently prepping the brass for that load. As a side note the factory Hornady 143 ELDX didn't shoot that well, but barrel was new and speeds were was less than advertised. I believe I can push them passed 3000 fps with no problem.

Looked at the load data today:
1 fired hornady brass
OAL length 2.945
59.5 Gr H 1000
WLR primer
Berger 156
2936 fps
SD 3
ES 6
Hope that helps your buddy or someone else here.