308 Win cases modified to take shotgun primers...

[Ray123]

Primer shortage lead to trying modified 308 cases to take shotgun primers. And I had no interest in reloading primers, as some discussed.
This alteration compromises the full strength of the case, plus the shotgun primer. So I milled a case to check on how much metal was left...decided on less than 30,000 PSI, Not CUP...as shotguns are 12000 psi or less.This would be subsonic and a survival type endeavor. Fired 155, 168, 175, and 200 gr match bullets at 50 yards. All groups were 1/2" 3 shot groups to .916" 5 shot
velocities subsonic to 1320 fps with fairly good S/D. The 200 mk went sideways as it was a 12 twist barrel as expected. But it was a successful experiment, and plausible in case of emergency. The powder involved was Trail Boss 10.5 to 13.8 grains pushing the envelope to higher pressures and higher velocities...but this is a low pressure subsonic survival endeavor, and 10 to 13 grains of Trail Boss really fills the case well and responds well to the shotgun primer. Worth the effort probably not, ...but its there if ya "need" it to shoot.

 

[divingin]

Have you tried popping the primer out of the collar of the shotgun primer?

 

[Ray123]

Nope, hadn't played with the shotgun battery cup, anvil, primer cup, or priming mixture...or try to use the priming mixture to reoad rifle primers. This is too easy once the case is modified to use the complete shotgun primer. I have a 5 gallon bucket of discarded 308 brass, and used the 40 times fired 308 Lapua out of the scrap bucket for this project...and now have tight primer pockets once again. Size deprive and prime, then load em on the Dillon progressive. Just 10 to 11 grains of Trailboss fills much of the case you can use any bullet from 150 grain to 200 gr over that change of powder, as long as the bullet doesn't even start to compress the Trailboss. Versatile and fairly quick and it works. Hodgdon has subsonic 308 data for Clays, and Titegroup, but in tiny quantities that do not fill up the case like Trailboss, where it's all almost impossible to screw up. I even use Trailboss for low velocity 50BMG loads about 52 grains does an accurate sub for the 50BMG.

 

[ebb]

Cool experiment! Thanks for posting! Guys at cast bullets are boring 38special to take large pistol primers kind of a sideways move but depending on what you have it may keep you shooting. I would like to bore oversize my 300 and 7mmRUM primer pockets and have some type of steel or stainless-steel insert that will have the right sized ID to make tight pockets again.

 

[STORM2]

Stories like this remind me to by another case of primer tomorrow.

 

[Mike Casselton]

I did an experiment last month with 300 BO subsonic loads.
Since they operate under 35ksi, I loaded a few with some very old (like 50 yr old) small pistol primers.
They went bang and stayed right at 1" @ 50 yards.
The dent in the primer was pretty deep, but they functioned fine.
Another backup plan if someone might need it.

Disclaimer: test these for yourself and figure out your own load.

 

[hoz53]

Primer shortage lead to trying modified 308 cases to take shotgun primers. And I had no interest in reloading primers, as some discussed.
This alteration compromises the full strength of the case, plus the shotgun primer. So I milled a case to check on how much metal was left...decided on less than 30,000 PSI, Not CUP...as shotguns are 12000 psi or less.This would be subsonic and a survival type endeavor. Fired 155, 168, 175, and 200 gr match bullets at 50 yards. All groups were 1/2" 3 shot groups to .916" 5 shot
velocities subsonic to 1320 fps with fairly good S/D. The 200 mk went sideways as it was a 12 twist barrel as expected. But it was a successful experiment, and plausible in case of emergency. The powder involved was Trail Boss 10.5 to 13.8 grains pushing the envelope to higher pressures and higher velocities...but this is a low pressure subsonic survival endeavor, and 10 to 13 grains of Trail Boss really fills the case well and responds well to the shotgun primer. Worth the effort probably not, ...but its there if ya "need" it to shoot.

isnt the shotshell primer tall enough that a person would have to bore out the whole bottom of the primer pocket?

 

[Ray123]

isnt the shotshell primer tall enough that a person would have to bore out the whole bottom of the primer pocket?

Yes, absolutely....that's why the case integrity is compromised and dictates low pressure loads, & shotgun cups are thinner than small rifle. I milled the altered case in half to compare with a 9 mm Luger case also milled in half to measure cross-section areas. There is a lot more brass in the head of the alter 308 than the 9mm but I believe the thin shotgun primer cups make it necessary to keep the pressure low, most shotguns run a max 12,000 PSI. These have been run to aprox 25,800 to 27,100 psi with no ill effects, and good accuracy, according to Hodgdon data for Trailboss, and reached 1320 fps with 168 MK, staying inside that pressure. Some powders show much faster velocities but they are at 32 to 35 thousand PSI, and too low a powder charge with these powders cause detonation to occur.
This more of a survival, no primers situation where if you find shotgun primers you can make them work. I've also taken 5.56 brass to take LR primers... just in case I need to. Or make 6 mm ARC out of 308 brass has been accomplished. In Hard times, Hard measures must be adopted. Like the $3 WW2 disposable Liberator pistol, very close range weapon and throw it away when run out the 5 or 6 rds ...

 

[Ray123]

Cool experiment! Thanks for posting! Guys at cast bullets are boring 38special to take large pistol primers kind of a sideways move but depending on what you have it may keep you shooting. I would like to bore oversize my 300 and 7mmRUM primer pockets and have some type of steel or stainless-steel insert that will have the right sized ID to make tight pockets again.

That too is possible, with stainless steel only, but the work involved would be something I'd only most likely do for myself, as cases get more expensive and unavailable...plus the cases thin about .200 down from the rim and sooner or later case head separation will occur, and why I scrap many Lapua 308 cases when the primer pocket is still okay. I'd try making a die as an experiment and size the head down a few thousanths to see if the primer pockets tighten up, and loosen after firing of a standard load....but ya need a real heavy duty press to size that much hard brass, a push through die and special industrial sizing lubricant. There was a company about 20 yrs ago that made stainless steel case heads with brass bodies, and they had load data to run your 30-06 to like 80,000 PSI. Then the bi-metal , stainless head aluminum body, 9 mm cases that ran high pressure & high velocities for 10 reloads, advertised, and weren't too expensive, unlike the Stainless head rifle cases. Being a retired machinist with 2 lathes and a Bridgeport mill and most all the tooling I need. Plus plenty of time I do all kinds of "out
of the box" experiments, and post a few. No firearm or cartridge is off limits to alteration or experimentation. But telling people how and what is done, tends to help very few, as most do not possess the machine tools and knowledge to do it for themselves. But just incase it helps one or two I put some of the information out there...it can be done, if your interested. Most everything can be accomplished, even if your first few ideas fail, there is another idea waiting in the mind that will solve the problem. Keep on shootin.

 

[ebb]

Ive seen (on the web) the two piece cases. Some of the guys that were making the 2000yd elk kills were using them. I've thought of a die that would be two piece that would go around the case head that would be used in a hydraulic press to compress the head, but its still cheaper to just get new brass. I too have a lathe and a Chinese Bridgeport, but I was a carpenter and have very limited knowledge on how to use them.

 

[Angler4570]

Many years ago they would knock out primer in shotgun primer and replace with large rifle primer I believe. I think it was Herter's that made the kit.