Suggestions for cast/coated bullets for S&W 625 .45 ACP revolver?

[revchuck38]

Nerd alert!

I've always used 230 grn because that's the weight that was originally used for the cartridge.

.45 ACP was originally loaded with a 200-grain JRN for the 1905. The 230-grain load came later. That said, I use the 230s in all my .45 ACP loads except for my M22-4, where I use 225-grain RNFPs so I can crimp them in the crimp groove.

[03RN]

How much velocity loss should I expect in my .45colt mountain gun milled for moon clips and shooting ACP?

I shot the other day and was losing 200fps +/- compared to 4-5" 1911s.

Quite honestly it's not a big deal because I only got it milled for playing in gun games and plan on using.45 colt when carrying it.

Just curious

[willie]

How much velocity loss should I expect in my .45colt mountain gun milled for moon clips and shooting ACP?

I shot the other day and was losing 200fps +/- compared to 4-5" 1911s.

Quite honestly it's not a big deal because I only got it milled for playing in gun games and plan on using.45 colt when carrying it.

Just curious

I can't imagine that much velocity loss. I would have guessed no more than 50 fps compared to the 1911. Something is amiss.

Measure the revolver fired ACP cases and compare them to the same shot in your 1911. Also compare this reading to diameter of fired Long Colt cases. In the revolver fired cases, a smoky black residue from burned powder would indicate that cases are not expanding enough to seal chambers. Hence some gas is not propelling the bullet. The Long Colt chambers are larger in diameter than 45 ACP chambers in a ACP revolver made for this caliber.

This smoky residue is seen in fired 45 Colt cases when the powder charge is too light. I predict that increasing the ACP powder charge will resolve this by making the cases expand enough to seal chambers.

[revchuck38]

The .45 ACP case is .004" narrower and .387" shorter than the .45 Colt case. Googling chamber dimensions showed .483-.488" for .45 Colt and .4744" at the case mouth and .4796" at the base for .45 ACP. That's a lot of room for gas to escape around both the case and the bullet on firing. Note that it's common to find a 30-50 fps loss firing .38 Special ammo from a .357 Mag chamber compared to a .38 chamber, and that's with a .1" longer chamber in the .357 and all other dimensions the same. Plus, there's some velocity loss due to the barrel/cylinder gap. My guess is that that's what's causing the velocity difference.

[03RN]

Fired cases from both ACP and colt at the mouth measure 0.478.

I don't have any fired brass from my 1911s

[Velo Dog]

How much velocity loss should I expect in my .45colt mountain gun milled for moon clips and shooting ACP?

I shot the other day and was losing 200fps +/- compared to 4-5" 1911s.

Similar velocity loss in this video. Trigger Warning, contains Clear Ballistics gel and Strasbourg references



.45 GAP might actually give higher velocity than standard pressure .45 ACP

[revchuck38]

Trigger Warning, contains Clear Ballistics gel and Strasbourg references.

🤣

[03RN]

I watch most of his videos and that's actually what prompted my post.