S&W Mountain Gun Cylinder Work - 45 Colt/45 ACP

[meef]

Looking for opinions and input - all kinds.

I've just gotten hold of a S&W Model 625 Mountain gun in 45 Colt. It's a beauty! A 625-6 made in 1997.

Am pondering/considering whether to get the cylinder machined to allow it to use 45 ACP with moon clips in addition to the 45 Colt cartridge.

I've heard a few good things about such a conversion from various internet sources, but there's something that still bugs me.

Wouldn't the bullet in the shorter 45 ACP cartridge have to travel a bit further in the cylinder before entering the barrel, and wouldn't this possibly be less than a good thing?

I really like the idea of being able to use both cartridges in the same gun, but can't quite shake the above concern.

Help me out here.

 

[9mmepiphany]

i'd think a bigger issue would be the different bullet diameters as the .45 ACP uses a .452 bullet while the .45 Colt uses a .454 one

 

[Action_Can_Do]

Whether that bullet jump means anything is a matter of debate. Different opinions from different folks. Ruger makes a blackhawk that fires both 45 auto and 45 colt, so I don't know if there would be a bullet diameter problem.

 

[ReloaderFred]

The .45 Colt hasn't used a .454" diameter bullet for many, many years. All current .45 Colt and .45 acp firearms are made with .452" diameter barrels.

I once owned a S&W Model 25-2, .45 acp revolver. I sold it because it was such a large revolver, with very little bite. I wouldn't modify the cylinder on that revolver, if it was my gun. If you want light loads, just load them lighter, or buy Cowboy loads if you don't reload yourself.

Hope this helps.

Fred

 

[9mmepiphany]

i will say that i didn't use the word "problem" as i think "issue" is a bit different...but then English is my 2nd language.

Ruger seems to do OK with their Single-Six in .22lr and .22mag too, but their is a bullet diameter difference also and they bore their barrels for the larger slug

 

[9mmepiphany]

The .45 Colt hasn't used a .454" diameter bullet for many, many years. All current .45 Colt and .45 acp firearms are made with .452" diameter barrels

i don't reload and wasn't aware of this. my friend who shoots SASS was the one who told me about the difference in slug sizes

 

[DWFan]

It isn't the distance to the barrel, but the distance to the cylinder throats. With the .45 ACP in a .45 Colt chamber, the bullet has an additional .300" to the throats; far enough for the bullet to nearly if not completely clear the case. So you have a .452" bullet travelling in a .476" to .480" bore and hope it lines itself up properly to smoothly enter the throat while gasses from the case flow around it.

 

[Stainz]

Since you must leave a vestige of the .45 Colt's cylinder outside ring to head-space the .45 Colt rim by, you wouldn't be able to load .45 Auto Rim. I considered it as well for my second 625MG, but left it unaltered. The .45 Colt is a neat old round - with it's newer/shorter sibling, the .45 Schoffield, a viable alternative for milder loads. Think it over carefully.

Stainz

PS I have a 625JM for dedicated .45 ACP/AR use.

 

[meef]

Whether that bullet jump means anything is a matter of debate. Different opinions from different folks. Ruger makes a blackhawk that fires both 45 auto and 45 colt, so I don't know if there would be a bullet diameter problem.

Yes they do, but they have two cylinders to address the issue, I believe - not the one-size-fits-all that I'd like to achieve.

I once owned a S&W Model 25-2, .45 acp revolver. I sold it because it was such a large revolver, with very little bite. I wouldn't modify the cylinder on that revolver, if it was my gun. If you want light loads, just load them lighter, or buy Cowboy loads if you don't reload yourself.

I'm not so much looking for the lighter load aspect, but the ability to use the 45 ACP of which I already have many, many rounds. I do reload, however, so I do have infinite (or at least many) options in the load department.

Ruger seems to do OK with their Single-Six in .22lr and .22mag too, but their is a bullet diameter difference also and they bore their barrels for the larger slug.

Once again, Ruger handles the issue by supplying two cylinders with the gun.

It isn't the distance to the barrel, but the distance to the cylinder throats. With the .45 ACP in a .45 Colt chamber, the bullet has an additional .300" to the throats; far enough for the bullet to nearly if not completely clear the case. So you have a .452" bullet traveling in a .476" to .480" bore and hope it lines itself up properly to smoothly enter the throat while gasses from the case flow around it.

Now this really hits to one of my concerns, maybe the primary one. I'd like to know if this is really a problem - seems like it would/could be. And yet, there are several places that do the 45 Colt cylinder machining and I've read where people who get it done seem to like it. I have yet to be able to find anybody who complained about the results.

Since you must leave a vestige of the .45 Colt's cylinder outside ring to head-space the .45 Colt rim by, you wouldn't be able to load .45 Auto Rim.

No problem there, I've no interest in the Auto Rim. I have too many calibers already.

The .45 Colt is a neat old round - with it's newer/shorter sibling, the .45 Schoffield, a viable alternative for milder loads. Think it over carefully.

Believe me, I am. That's the reason for this thread. I'm hesitant to modify any gun's working parts, especially a piece as nice as the 625-6.

I have a 625JM for dedicated .45 ACP/AR use.

That's a whole 'nuther gun. I'm already gun poor as it is.

I'm considering possibly buying another 45 Colt cylinder and getting it machined. If I like it, great. If not, I could always sell it on GunBroker and would simply replace the original cylinder back on the gun.

Good input. I'm listening.

 

[Marlin 45 carbine]

uumm, .45acp jacketed slugs are .451 dia.
cast usually are .452, at least in my experience - all 'plinking' loads I shoot now are 200gr cast rnfp's due to big price jumps in jacketed.

 

[StrawHat]

Another option and perhaps better than using either ACP or S&W brass is the 45 Special.

http://www.cowboy45special.com/

Basically an ACP length cartridge with the LC rim. Works in all revolvers chambered for the 45 Long Colt and reloads with the LC shell holder and 45 ACP dies.

AS for the long bullet jump from the short case to the leade, I competed with a 357 Magnum revolver and shot 38 Specials from it. It was accurate enough to win many matches.

 

[meef]

AS for the long bullet jump from the short case to the leade, I competed with a 357 Magnum revolver and shot 38 Specials from it. It was accurate enough to win many matches.

Very good example. Can anybody out there refute this or maybe explain why it's an apples-to-oranges illustration, or why it's not?

 

[meef]

Another option and perhaps better than using either ACP or S&W brass is the 45 Special. Basically an ACP length cartridge with the LC rim. Works in all revolvers chambered for the 45 Long Colt and reloads with the LC shell holder and 45 ACP dies.

Looks very interesting. Appears to be a good way to go for the much lighter loads, and they explain it well on your supplied link.

I would, however, like the option to use full moon clips with the 45 ACP.

Choices, choices.

Keep 'em coming.

I'm learning stuff here.....

 

[RugRev]

Another Cylinder

A second cylinder sounds good. Perhaps start with a smaller caliber cylinder of about the same length as the .45 Colt if such exist (.357, .41 mag, .44 mag) if you can find one so the throat issue can be addressed and chamber it for .45 ACP.

 

[Canuck-IL]

AS for the long bullet jump from the short case to the leade, I competed with a 357 Magnum revolver and shot 38 Specials from it. It was accurate enough to win many matches.

Very good example. Can anybody out there refute this or maybe explain why it's an apples-to-oranges illustration, or why it's not?

The case length diff for 357:38Spc is .12 - a bunch longer in 45 Colt:ACP
/Bryan

 

[DWFan]

Quote from DWFan:
It isn't the distance to the barrel, but the distance to the cylinder throats. With the .45 ACP in a .45 Colt chamber, the bullet has an additional .300" to the throats; far enough for the bullet to nearly if not completely clear the case. So you have a .452" bullet traveling in a .476" to .480" bore and hope it lines itself up properly to smoothly enter the throat while gasses from the case flow around it.
Quote from meef:
Now this really hits to one of my concerns, maybe the primary one. I'd like to know if this is really a problem - seems like it would/could be. And yet, there are several places that do the 45 Colt cylinder machining and I've read where people who get it done seem to like it. I have yet to be able to find anybody who complained about the results.

I can't address the .45 ACP/Colt setup but, in my Dan Wesson SuperMag, the switch from the .357 Maximum to the .360 Dan Wesson to the Magnum to the .38 Special is dramatic. The Special has never shot anything less than an 8" group at 50 yards. The Magnum is 3"-4" at the same distance. The .360 DW closes that to 2" while the Maximum is under an inch. For that reason I download the Maximum instead of using the Magnum or Special as plinking loads. This freebore distance affecting accuracy problem also applies to the Contender and was enough of a concern that Mike Bellm designed a special chamber for the Maximum that very closely resembles a revolver chamber. I read a post somewhere, maybe on this site, where a S&W M610 rechambered to 10mm Mag had the same tendencies when going from 10mm Mag to 10mm to .40 S&W.

 

[Slamfire]

Starting with this 45 LC, in 1989, Smith and Wesson went from .455 ball throat diameters to .452. Prior to that year to get acceptable accuracy from a S&W 45 LC you had to shoot .454. Since then, you can shoot .452



Are you aware understand that you will have to zero your pistol after changing cartridges? I consider this a bother and enough of a bother to consider a 45LC/45ACP dual use revolver a poor idea.

I don't even like moon clips. I have a M1917. Moonclips are a pain to reload and unload. The better choice is 45AR rim brass, but then, all you really have is a super short cut 45LC.

This is my personal opinion, but my 45LC will do every a 45ACP revolver will do, and more. I can shoot 255's at lower pressure, or if I wanted to, shoot even heavier loads. I can also shoot 230's, which for the life of me, I don't see a need in a N frame revolver. The only time I have shot 230 FMJ in a 45Lc was to scrap out lead fouling.

I like my 45LC Mountain revolver as is.



This guy claims "45 LC cylinders can be cut to shoot both ACP and LC" http://www.pinnacle-guns.com/revolver.asp

 

[rcmodel]

It's also worth noting that the cylinder stop on the side of the frame is further foreward on the shorter .45 ACP cylinder guns.

If you built a convertable using two cylinders on a .45 ACP gun, the .45 Colt cylinder would not open all the way unless a relief groove is turned in the rear edge to miss the stop.
And it would not close because it would hit the barrel shank.

A .45 ACP cylinder on a .45 LC gun would not only be a sloppy fit when open, but except for a few fairly rare models, would not be long enough to reach the barrel on a .45 Colt gun.

rc

 

[Rem.222]

Go for it. I think it's the best way to go in a 45 Colt mtn gun. A year ago I almost did the very thing your asking but funds ran out.

 

[meef]

Okay. So based on what I'm hearing - here's what I'm thinking....

If I get the cylinder modified/machined - then that shouldn't have any effect one way or the other on shooting 45 Colt out of the gun since everything still connects the same as with an unmodified gun.

The 45 ACP would be a different story for the reasons previously stated and would probably (certainly?) not shoot to where the sights are set for the 45 Colt.

The way I see it - so what?

The 45 ACP would still probably hit minute of bad guy or pie plate at 7 yards which would be satisfactory for me. I'm not looking to have a match grade revolver here.

The upside is the ability to shoot two different cartridges in the same gun by merely using full moon clips.

The downside is.....?

Based on the above criteria, you tell me.

 

[cprher]

Having thought about this type of work long and hard and having done some very similar modifications, here are my 2 cents worth.
a. The headspace issues you introduce are non-trivial. If they both had similar rim dimensions, then OK, but the difference between 45 Colt and 45ACP rims is significant.
b. The frame lug and difference in cylinder length is problematical. Closing the cylinder after loading is aided by having the right lug, shaped and angled to help ensure the rims don't jam against the breech face. That was a significant issue on a Model 28 I converted to 45 ACP. The gunsmith overlooked that little fact and now I have to be very careful to close the cylinder properly. It's a target gun so no big deal, but on a defense weapon, no way it would be acceptable.
c. The accuracy would suffer, but then you aren't target shooting so as you say minute of badguy is good enough. However, if you are using it for self defense then being intimately familiar with where the gun shoots is critical. Jumping between loads and possibly not remembering which sight setting is on the gun is not helping achieve success. Also, there is a lot of good advice out on the web that the gun you use for self defense should be left as it comes from the factory as much as possible. Otherwise the opposition has a chance of labeling you a "gunslinger" with rather bad results.
d. You ruin the value of an otherwise highly desireable gun. The 625 in 45 Colt routinely draws better $$$ than the 45 ACP version. Take advantage of that. Sell the 45 Colt and get the 45 ACP. If you don't reload, don't mess with the 45 Colt. In terms of the ammo available the 45 ACP has it all over the Colt. If you reload like I do, it's a different matter, but since you don't you are needlessly complicating things.

Enjoy shooting it whatever you do.
Keith

 

[StrawHat]

Any time you change bullet weights or loads in a revovler you can cause a change in the point of impact. Even at seven yards. Unfortunately, the one size fits all concept is a good theory but in practice it rarely works out.

Fortunately, S&W makes both revovlers and they can be found on the used market with a bit of searching. Perhaps not your ideal solution but if you are thinking about a SD piece, I recommend one that is as simple and straightforward as possible.

 

[unspellable]

MY advice is to do nothing and be happy. If you shave the cylinder to take 45 ACP you will have ruled out the 45 Colt as the head space will be way too much for the 45 Colt. In addition you will have weakened the extractor star. It's not possible to fire 45 Colt and 45 ACP from the same cylinder due to the rather drastic difference in head space. That's why a Ruger Blackhawk convertible has two cylinders.

 

[StrawHat]

cprher

...b. The frame lug and difference in cylinder length is problematical. Closing the cylinder after loading is aided by having the right lug, shaped and angled to help ensure the rims don't jam against the breech face. That was a significant issue on a Model 28 I converted to 45 ACP. The gunsmith overlooked that little fact and now I have to be very careful to close the cylinder properly. It's a target gun so no big deal, but on a defense weapon, no way it would be acceptable.Enjoy shooting it whatever you do.
Keith ...

Keith,

The frame lug is a replaceable part. I had it done when I converted my 28-2 to 45 ACP.

Part #29 031030000 $2.90 X FRAME LUG

from

http://www.smith-wesson.com/wcsstore/SmWesson/upload/other/RevPartsList_Retail.pdf

If no longer available, it is a press fit piece and a bit of round stock can be used, and filed to fit after it is in place.

Good luck

 

[Jim Watson]

The cut that Pinnacle makes to accept clips on a .45 Colt - .45 ACP conversion does not change the outer periphery of the rear face of the cylinder. This leaves some original surface for the rim of the .45 Colt to headspace on and leaves the cylinder-to-frame lug relationship unaltered.

That does not mean there are not unanswered questions.

I don't know how the long jump through the Colt chamber will affect accuracy and velocity of .45 ACP bullets.
I don't know if the difference in bullet weight might move the point of impact clear out of range of the sight adjustment... which is not great on S&W revolvers.

I think I would trade guns. But then I would not have bought the .45 Colt in the first place, I got that out of my system years ago.