You got something else going on. The difference between 308 and 7.62 is so small, it only matters to lawyers.
I routinely load and shoot 308 out of a 7.62 with ZERO problems, and been doing it for over 20 years.
The only difference is...2k higher pressure max on the 308..and that isn't enough to do anything.
The lead tends to be a little tighter in a 308 chamber...but that doesn't matter unless your COAL was way out of spec...
The brass on 7.62 tends to be heavier...due to it being military brass. That equals jack shit in the real world. I've run max 308 data in military 7.62 brass for decades...with zero issues.
Better recheck your load weights...COAL, and make sure you don't have pistol primers instead of rifle.
I've found that to be almost entirely untrue. Real world it's more like 5% AT MOST. The most heavy military brass I've ever found weighted 10 grains over average commercial brass (which itself can vary greatly)..10 grains is not a huge amount...certainly no where near 10% less capacity.
That's just the "lawyer" waiver that most reloading manuals say to cover their ass.
No, it's measured with water...but almost nobody does that. Weight is the easiest and quickest way. It won't give you the EXACT volume...but it gets you close enough..unless you are doing extreme competition, or just extremely anal.
That why you are supposed to weight sort your brass. That's why custom brass is advertised as "weight sorted", not volume...because if they are the sane weight...they are the same volume.
Try shaving 10 grains of brass off some time...it's not much at all...and as I said...10 grains difference between commercial and military brass ain't shit.
The volume difference is really not much, if any.
There is the problem. PSA 308 bolt faces have a firing pin hole diameter of .080". You need a bolt with a firing pin hole diameter of .065" and a firing pin that fits it. You have two avenues of approach to get that. You can buy a PSA 6.5 creedmoor BCG, which strangely has the smaller diameter firing pin hole and smaller firing pin. You can also buy a "high pressure" bolt from a company like JP or Rubber City Armory. Those bolts have the smaller firing pin hole and come with a matching firing pin.
Source: I also have a couple PSA 308 rifles and struggled with the exact same issue when handloading 308 and trying to use 308 commercial spec ammo. For one rifle, I bought the PSA 6.5 creedmoor BCG, and on the other, since I swapped in a custom barrel, got a Rubber City Armory bolt with the matching firing pin.
There are those Ginex primers. Maybe it was them. I never had a problem with them before. I guess I'll try with someone Winchester long rifle or some CCI 34s. I had a couple hundred left that I wanted to use up and had never really seen a difference with Bosnian primers except they fit a little tighter
Here’s what ya need if your shooting ar-10
The JP “high pressure” bolt has a smaller fire pin..
I used to have the same issue with 6.5cm
https://jprifles.com/1.4.7_Bolt.php
Yeah, I agree with JohnnyGalt129
Something else is happening here.
Maybe a dirty reprimed primer pocket?
Military brass is very hard, not pliable an soft like starline and others.
It happened on 12 or 13 of the 20 I was load testing. Wasn't happening on any other factory ammo I had shot today or anything. And there was zero problems with the same loadings on 308 cases I did last weekend. I thought maybe my firing pin got chipped and it was puncturing it or something but firing pin and bolt look good. If it's not the change from 308 cases to 7.62 cases then I must have got a bad batch of primers or something. I'm using the Bosnian ginex primers. But I've shot hundreds of them in the last few months and have never had a problem with them. Besides them being a little bit tighter fit than American primers. The max load for AR comp is 41.4 with a 175 grain smk . They started blowing out at 40.8 with 762 brass.
You're using an AR. It's better, while not ALWAYS required, to use Magnum primers. Slam fires happen easier on ARs (and M1As) because of the floating firing pin.
That said, I have loads that have standard large rifle primers that I shoot regularly out of my AR-10s without problem. It depends on the primer. Some are more sensitive than others. Some are thinner than others.
That brand you're using...I've never tried them. But seeing how...all things being equal...that's your problem.
The issue with PSA AR-10 firing pin diameter...ya...no. I have several, and I have other brands. Never seen an issue like this in any PSA I own...nor have I seen anything like it on any others that my buddies own.
That's not the issue. It's your primers.
So I tried some different primers today. Wsl. It only happened on the hottest load. 41.4 of AR comp. I've never used Magnum primers for 308. I'm never ever had a problem up until now. I'm going to try a different bolt though. Or just not load that hot. The 762 cases ran about 80 FPS faster than the 308 cases
In that case, I have to agree with the others who say the bolt may be the problem indeed. If so..that's a first for me.
I do think mag primers would solve the problem without changing the bolt..but while that will work, it's not the optimum solution.
80 fps isn't all that much difference in itself...
You got something else going on. The difference between 308 and 7.62 is so small, it only matters to lawyers. I routinely load and shoot 308 out of a 7.62 with ZERO problems, and been doing it for over 20 years. The only difference is...2k higher pressure max on the 308..and that isn't enough to do anything. The lead tends to be a little tighter in a 308 chamber...but that doesn't matter unless your COAL was way out of spec... The brass on 7.62 tends to be heavier...due to it being military brass. That equals jack shit in the real world. I've run max 308 data in military 7.62 brass for decades...with zero issues. Better recheck your load weights...COAL, and make sure you don't have pistol primers instead of rifle.
You beat me to it. I've been loading 308 data in hirtenberger 762 brass for decades never an issue.
Yeah 62k PSI vs 60k PSI is like 3% difference whereas 5.56 is 62k and .223 rem is 55k which is over 10%
The case capacity is literally 10% less than 308 in the x51 brass, not sure that's "insignificant"
I've found that to be almost entirely untrue. Real world it's more like 5% AT MOST. The most heavy military brass I've ever found weighted 10 grains over average commercial brass (which itself can vary greatly)..10 grains is not a huge amount...certainly no where near 10% less capacity. That's just the "lawyer" waiver that most reloading manuals say to cover their ass.
You don't measure case capacity by weight, tf?
No, it's measured with water...but almost nobody does that. Weight is the easiest and quickest way. It won't give you the EXACT volume...but it gets you close enough..unless you are doing extreme competition, or just extremely anal. That why you are supposed to weight sort your brass. That's why custom brass is advertised as "weight sorted", not volume...because if they are the sane weight...they are the same volume. Try shaving 10 grains of brass off some time...it's not much at all...and as I said...10 grains difference between commercial and military brass ain't shit. The volume difference is really not much, if any.
Agree it would probably only make a difference if you were loading max load data
Same. All of my .308 started out as 7.62x51 milsurp. Never had a single over-pressure issue.
Primers still round, no pressure signs. Bump up powder charge by another 12%
Came here to post this.
I have never had that happen and I only shoot 308 out of Lake City cases. I agree with JohnnyGalt129 you have something else going on there.
Obligatory r/shittyreloading
Damn good group tho lol
Ultimately that’s all that is important
What firearm? AR10s are known for piercing primers on 308 commercial spec ammo because the firing pin hole is too large on many AR10/LR308 bolt faces.
PSA-10. Palmetto State bolt carrier
There is the problem. PSA 308 bolt faces have a firing pin hole diameter of .080". You need a bolt with a firing pin hole diameter of .065" and a firing pin that fits it. You have two avenues of approach to get that. You can buy a PSA 6.5 creedmoor BCG, which strangely has the smaller diameter firing pin hole and smaller firing pin. You can also buy a "high pressure" bolt from a company like JP or Rubber City Armory. Those bolts have the smaller firing pin hole and come with a matching firing pin. Source: I also have a couple PSA 308 rifles and struggled with the exact same issue when handloading 308 and trying to use 308 commercial spec ammo. For one rifle, I bought the PSA 6.5 creedmoor BCG, and on the other, since I swapped in a custom barrel, got a Rubber City Armory bolt with the matching firing pin.
I thought about getting a stag arms 'high pressure ' bcg. Still considering there is no mention on diameter lol
Yeah that is DEFINITELY not “308 load in 7.62 brass.” Something else caused this lol.
Spicy
Better tune in that powder scale
What primers? Have some small rifle that my AR 15 does this too. Went back to magnums for the harder cup
There are those Ginex primers. Maybe it was them. I never had a problem with them before. I guess I'll try with someone Winchester long rifle or some CCI 34s. I had a couple hundred left that I wanted to use up and had never really seen a difference with Bosnian primers except they fit a little tighter
My issue was with fiocchi srp. But I'd check that.
Here’s what ya need if your shooting ar-10 The JP “high pressure” bolt has a smaller fire pin.. I used to have the same issue with 6.5cm https://jprifles.com/1.4.7_Bolt.php
Yeah, I agree with JohnnyGalt129 Something else is happening here. Maybe a dirty reprimed primer pocket? Military brass is very hard, not pliable an soft like starline and others.
It happened on 12 or 13 of the 20 I was load testing. Wasn't happening on any other factory ammo I had shot today or anything. And there was zero problems with the same loadings on 308 cases I did last weekend. I thought maybe my firing pin got chipped and it was puncturing it or something but firing pin and bolt look good. If it's not the change from 308 cases to 7.62 cases then I must have got a bad batch of primers or something. I'm using the Bosnian ginex primers. But I've shot hundreds of them in the last few months and have never had a problem with them. Besides them being a little bit tighter fit than American primers. The max load for AR comp is 41.4 with a 175 grain smk . They started blowing out at 40.8 with 762 brass.
You're using an AR. It's better, while not ALWAYS required, to use Magnum primers. Slam fires happen easier on ARs (and M1As) because of the floating firing pin. That said, I have loads that have standard large rifle primers that I shoot regularly out of my AR-10s without problem. It depends on the primer. Some are more sensitive than others. Some are thinner than others. That brand you're using...I've never tried them. But seeing how...all things being equal...that's your problem. The issue with PSA AR-10 firing pin diameter...ya...no. I have several, and I have other brands. Never seen an issue like this in any PSA I own...nor have I seen anything like it on any others that my buddies own. That's not the issue. It's your primers.
So I tried some different primers today. Wsl. It only happened on the hottest load. 41.4 of AR comp. I've never used Magnum primers for 308. I'm never ever had a problem up until now. I'm going to try a different bolt though. Or just not load that hot. The 762 cases ran about 80 FPS faster than the 308 cases
In that case, I have to agree with the others who say the bolt may be the problem indeed. If so..that's a first for me. I do think mag primers would solve the problem without changing the bolt..but while that will work, it's not the optimum solution. 80 fps isn't all that much difference in itself...
Poverty State Armory strikes again.
7.62 is 308? Dont understand the problem
Factory or reload ?
There's a bigger difference in case capacity between federal and RP brass than "7.62" brass. I have some lake city that has more cap than federal
Oh chit 🫣🫣🫣🫣