45ACP made from 308...?

[Spec.-K]

Hi everyone.
Has anybody here had any experience making 45acp from trimming 308 brass?
I've read about the concept, but haven't found much on how it works/performs.

Anyone here know first hand?
Please share!
-K

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[deadshot2]

There are two ways to look at this. Can it be done and should it be done? Probably can but the cases don't share the same dimensions. the .308 case has a larger extractor groove diameter. The rim/base of the .308 case is .006" smaller in diameter which will leave the case undersized for the .45acp chamber.

There is also the internal case dimensions to consider. the .308 case, especially military cases, has a tapered wall thickness which makes it thicker as it approaches the base. It's designed to operate up to 62,000 PSI so it has to be stronger. The .45acp case, only having to withstand 21,000 PSI, is more of a straight walled case only getting thicker at the radius where it joins the base. This can reduce the case capacity drastically.

Yes, one can probably do it but Should they?

Rather than rely on "Internet Advice" just take one case of each and cut them in half, lengthwise. Also compare dimensions for yourself with a good micrometer/caliper. The differences will be obvious and any resulting round produced from .308 will be "loose" with an extractor groove that may not behave well in your firearm.

Even if it worked flawlessly, unless one had a huge source of free .308 brass and lots of time on their hands, I can't see the advantage unless you are trying to design a high pressure cartridge for a low pressure gun.

 

[saxon]

about 30 years ago this first came up and i did try it,
first off cutting to length and then making a dummy round.
Test gun a MK IV ser 70 COLT 45
Operating the slide by hand it had no problem feeding or extracting.
BUT since the 308 as deadshot put it has a tapered wall thickness
You would have to machine the inside to be able to use the reloading die
Right, that is to say to expand and bell so that you could even reload it.
So I gave up, sure it can be done , sure you can get a higher pressure,
But for the cost and or the danger to the gun if you over do it,,,,,,
Now worth it and that was 30 odd years ago

 

[22many]

Now, I'm clueless when it comes to any type of reloading but why would you want to do this? Seems to me that 45 acp would be cheaper than 308.

 

[saxon]

Now, as to loads. You can run almost whatever you like because of the tremendously strong cases,
back in the day when colt was well COLT
it was a way of reloading HOTTER THEN HOT loads, but at risk of damaging the gun as far as i was concerned.
i mean when you can relaod see n osigns of pressure but you can feel the slide fully recoil againest the frame, time to ease off a bit

Now, I'm clueless when it comes to any type of reloading but why would you want to do this? Seems to me that 45 acp would be cheaper than 308.

 

[HollisOR]

Now, I'm clueless when it comes to any type of reloading but why would you want to do this? Seems to me that 45 acp would be cheaper than 308.

Yep much cheaper. So why? Trade the .308 brass for .45 acp brass, save a lot of time and makes the .308 person happy. I'll trade.

 

[deadshot2]

Now, as to loads. You can run almost whatever you like because of the tremendously strong cases,
back in the day when colt was well COLT
it was a way of reloading HOTTER THEN HOT loads, but at risk of damaging the gun as far as i was concerned.
i mean when you can relaod see n osigns of pressure but you can feel the slide fully recoil againest the frame, time to ease off a bit

Today, when people want to run "Hot Loads" in a semi-auto they just go find a 10mm.

 

[HollisOR]

Today, when people want to run "Hot Loads" in a semi-auto they just go find a 10mm.

Or if you want that .45 bullet flying at something like 1700 fps, get a 454 Casull.

 

[AMProducts]

I don't know why you would want to do this to load up regular .45ACP ammo, however back in the day there was a paper that discussed how to make .45 shotshells and uses .308 for the parent case, mostly because the alternative is using .45 Win Mag cases which are rare and expensive to buy.

If you're interested, here's the file: <broken link removed>