where do the bullets headspace at?

[markg]

This post used to be longer, but as I collected my thoughts on the topic, I semi-answered some of my own questions, so now the post is shorter.

My simplified question is:When shooting .40 sw through a M610 10mm revolver, or .45gap through a .45acp M625, do the cartridges headspace off the moonclip? What is the general opinion on accuracy when one uses the short rimless cartridges in guns chambered for longer ones?

Thanks.

[Randall M]

Via the full moon clips can be the only answer.

WHich is kinda confusing since the S&W .45 ACP
revolver are chambered to headspace still on the mouth
of the cartridge - I shoot a 625 .45 ACP with the
full moon clips, but also keep a good supply of loaded
.45 Auto RIm. I did some searching and found the tech
drawings and measurements for .45 Auto RIm and .45
Colt. The Colt has a regular thickness to the rim of approx.
.0615 and the AUto RIm has a bit thicker rim, .0910 approx
in order to position the primer/rear of the case in the same
relation to the firing pin.

I wonder if the .40 S&W in the 610 has some issues with this
and the 10MM Auto being better since that would headspace on
the full moon clips?

THe reason I ask is I would like a 610 as well.

Randall

[Randall M]

FYI - No experience with .45 GAP

R-

[FreeAmerican]

I shoot 40 out of my 610 all the time. Just like shooting a 38 out of a 357.

I have not tried the 45 gap in my 625 but I have also shot a lot of 45AR. In fact, I have a bunch of AR loaded up with 255 SWC intended for 45 Colt. I have shot a bunch of 230 and 200 SWC AR and they all have a point of impact the same as regular 200 and 230 ACP.

If you like the 625 you will love the 610. Most of the 40 I shot through her was before I really settled in on loading 10mm. After I got set up for 10mm and got my load, I have shot maybe a handful of 40.

[fltbed]

It is my understanding, (after reading a rather lengthy rant in Handloader magazine) that all the current S&W 45 acp revolvers will only headspace on the moonclip, as current S&W bean counters deem it cheaper to not cut a proper ACP chamber. “Why would anyone want to shoot it without moonclips”, is the standard company line today. Lack of accuracy, compared to the old style guns with proper chambers, seems to be a non issue with current S&W owners.

Does anyone have any first hand experience with this? I can’t see how cutting a different chamber could be cheaper.

Jeff

PS I stopped by my local gun shop and checked out a new S&W light weight Ti cylinder 45 acp (325?) and sure enough the rounds sit so far down into the chambers I couldn’t see how it could fire without moonclips.

[FreeAmerican]

Well, my 625 and my 1917 Smith (made around 1918) both have very sim chambers, you get hit or miss without clips in either. But even when you do it is a PITA to knock the empties out.

My 610 on the other hand has very clear cut throat. Pop 10mm in and it sits right up where it should.

Now here is my theory as to why that is.

notice a 38 /357, 44, 45 Colt etc. (std rimmed pistol cals) they do not have a chamber cut like an auto either. Keep in mind a lot of these rounds have a good ole roll crimp anyway. Soooo, I think the 625 were cut like that to allow the AR round to seat. But since you have the AR round, why sweat shooting ACP without clips??

[JWnTN]

Originally Posted by fltbed

It is my understanding, (after reading a rather lengthy rant in Handloader magazine) that all the current S&W 45 acp revolvers will only headspace on the moonclip, as current S&W bean counters deem it cheaper to not cut a proper ACP chamber....

Does anyone have any first hand experience with this? I can’t see how cutting a different chamber could be cheaper.

A couple friends of mine purchased 625's and had misfires when using .45 ACP rounds without the moon clips.