Model 25-2 chamber tolerance

[CWO USN]

I've read somewhere here and have been advised by forum members regarding chamber tolerance inherent with the early Model 25-2 .45ACPs that render some of the Model 25-2's inaccurate shooters.

What should be the chamber's correct measurement? Outside of taking a micrometer to the revolver, is there a quick check that can be performed to check the tolerances?

Thank you.

 

[Frank237]

Will a .451" or .452" slug push into the cylinder throats? As quick a way I can think of.

I use pin gauges. Never had any out of Spec issues with 25-2's but admit to not fooling around with but a few of them.

The 25-5 series had oversized throat issues though. Well doumented.

FN in MT

 

[CWO USN]

Thank you, Frank. I had a telephone conversation with one of the folks at Smith & Wesson. We had discussed the issue and he agreed that some of the earlier Model 25-2 did have tolerance issues (inside chamber dimensions) that prevents the gun from consistent tight groupings (accuracy regardless of brand ammo used). The measurement is within the chamber and the only solution is to replace the cylinder. Replacement would run somewhere north of $150.

 

[Tom C]

My old 25-2 has what could charitably be called casual chamber throats. My pin gages say .456". When I got it, it had the 6 ½" barrel and spit lead due to failure to align the chambers. I fixed the chamber alignment issue with a thicker hand and grinding lightly on the cylinder locking bolt. I also had the barrel cut to 5" and got a Performance Center trigger job and narrow, smooth trigger. Now, in spite of the generous throats, it shoots very well. I suppose I could send it to S&W and get a new cylinder, but it shoots well enough I haven't done it.

I also have a 625JM and 625PC, which both have tight .452" throats. Both shoot very well, but not noticeably better than the old 25-2.

 

[Vulcan Bob]

A quick check can be done with bullets. Useing a bullet only, not a loaded cartridge, take a jacketed .452 dia. bullet and holding the gun muzzel down with cylinder open drop the bullet into a chargeing hole, if it drops through and bounces off your toe it's too large, do this with all six. Then try a lead .454 dia. bullet wiped off to remove any lube or such, if it drops through you have one of the big un's about .456 or so. I will do this at a gun shop when checking one out prior to purchase. In general if it has a throat dia. of more than .452 a .454 dia. bullet will work ok and these in lead can be commonly bought. Hope this helps.

 

[CWO USN]

Tom,

I have looked into the "newer" model .45ACP but unfortunately they're currently offered in the shorter bbl length and I prefer the 6 1/2" for range work. Thanks for your inputs.

Bob,

Those are great ideas on how to spot check chamber tolerances. I don't hand load and will have to find both diameter bullets for the tests you pointed out. Thanks.

 

[epj]

Jacketed .45 bullets will be .451. You will need to find a lead .452. It needs to be miked, since some bullets sold as .452 are actually smaller. Digital calipers are available for under $30 and are very useful for a variety of tasks, especially if you reload.

 

[CWO USN]

epj - Thanks for providing the value of the .45ACP jacketed bullet. I'm going to call around town and see who has a lead measuring to that spec. Definitely will make sure that it trues out to .452. It'll be a handy measuring tool for future use.

This is a great forum! Thanks to all for taking the time and helping out.

 

[Gun 4 Fun]

Jacketed .45 bullets will be .451. You will need to find a lead .452. It needs to be miked, since some bullets sold as .452 are actually smaller. Digital calipers are available for under $30 and are very useful for a variety of tasks, especially if you reload.

Use Hornady bulets to check.
I have measured many, many, Hornady jacketed bullets, and they always mike right on at .452". Speers run .451" and Siearra's run as advertised at .4515".

CWO-USN-


A lot of very early 25-2" had oversized throats, as did many made from around the mis '70's on.

It isn't a chamber issue, and if the S&W employee told you that, he didn't know his vernacular. The throats, or what S&W call the "Ball end", are the problem. They should measure right around .452" ideally, but many of them on the 25-2 come in at .454"- .456".

 

[FlYFiShErMaN]

I have not checked my 25-5, but I have had no issues other than having to change targets out. It's a good shoot'en gun.

 

[brnoczech]

I have a 25-2 new in the presentation box from the late 1970's. Throats are right at .457. I was going to keep it as an investment, but have decided to go ahead and shoot it. I have some Mt. Baldy 45-270-SAA's on order which are stated to be .453 in diameter and Brinell hardness of 11, which is on the softer side. I am hoping that these will upset enough to shoot well. Hoping for loads in the 850FPS range for deer and hog hunting. If anyone has any experience with this bullet in this gun would appreciate any loads you have found satisfactory, or any other info you might have on cast bullets that would shoot well. Thanks

 

[avery53]

I just bought a 25-5 in Nickel, wish I had known about the throat issues.
Mine measures .454"-.4545", guess I'll have to get some oversize bullets to load.
BUT, it sure is purdy! lol

 

[Chuck Jones]

Avery, one fine day people are going to realize just how few nickel guns S&W actually made; so I'd hang on to that one.

/c

 

[Dave T]

Back in the late 1990s the club I belonged to wanted to start a revolver class for their steel (target) matches. I had a M25-2 built to suit me with a 5" barrel, round butt and action tuning for DA shooting. I found the best accuracy was from .454" cast bullets and fed that gun a steady diet of them. Shot it for almost 3 years before the timing, end shake and indexing became problems. Shipping guns had gotten very expensive in the interim since I'd had the gun built and I tried to have it tuned by a local gun smith. It never shot as well again so I sold it. Probably should have spent the money and sent it back to the guy who put it together for me...then I wouldn't have had to build another one recently. (smile)

Dave

 

[amazingflapjack]

I have been pleased shooting 255gr or 240 gr LSWC's out of my 25-2 and 625-8. I use Unique and a factory crimp die. The 255's are common to trhe .45LC-but they are both .452.

 

[Beaver]

25-3

One of my only S&W disappointments came with shooting a 25-3 that looked soooooo good. Great curb appeal. The throats were .456-.458. The gun would not shoot anything. I mean 8" groups at 25 yds. I'm not the greatest shot, but I can do 1-2" groups with a 48. Traded it for a model 18.

I'm buying a 25-5 with alpha-numerica serial # that I've been told repeatedly on this forum will have tight throats. I'm going to try the afor mentioned 45-270-SAA bullets. My buddy Stoney bought the mold, and the bullets look beautiful. I also bought some from Mt. Baldy and they shoot excellently in a custom 45 Colt I bought that was made up on a 29-2 frame. Engraved by Rudy Marek. We can size Stoneys' bullets to .451 or .452. I have some of both so I'll see what works.

I've been using Unique and PowerPistol 8-8.5gr. Nice mellow load. Killed a pig with it. One shot at 20-25yds, four little pigfeet pointed to the sky.

 

[GAMMD]

Just purchased a 25-2 possibly unfired would have learned about this problem after the fact will do some checking thanks for the heads up and maybe I'll get past this without gunsmitthing.

 

[brucev]

I do not understand. Why would S&W produce any revolver with such an error in the cylinder? Why would they not simply correct the problem? Is there any known explanation?

 

[Dave T]

I do not understand. Why would S&W produce any revolver with such an error in the cylinder? Why would they not simply correct the problem? Is there any known explanation?

I've been told (by folks who claim to know more about this stuff than me) that when the 1955 was introduced surplus Ball ammo was in great supply and cheep to buy. If you shoot ball with it's heavily jacketed bullets the over sized throats don't matter much. This doesn't justify Smith building them that way, but might explain why no one complained about 1955s and M25s.

Dave

 

[buckspen]

Model 25-2 Chamber Throats

I've had my eye on a 25-2 in a local gun shop for a few weeks. From the serial number it was made in the mid-1970's. It's a very nice gun, virtually unfired and in about 99% condition but with poorly fitting target grips.
I read this thread this morning and took my hole gauges and micrometer to the shop. The owner is a good friend and he allowed me to measure the chamber throats. Sure enough, they measured .456-.457, so I didn't purchase the revolver.
He also had a Thunder Ranch Model 22 on the shelf and I checked that one, too. The Thunder Ranch revolver had throats measuring .452-.453.
Thanks for the good information posted here, fellows.

- - - -Buckspen

 

[Ignatz]

Numrich Gun Parts shows a 625 cylinder for around $58.00. Would this drop in a 25-2? or would more 625 parts be needed? It might be a way to get the .452" throats reasonably priced.

 

[Milo Talon]

Glad I've been reading these postings.I've been thinking about trying to trade my 686-4 for a 25-something in 45 Colt.Guess I better back up and re-think this.

 

[cp1969]

It wasn't only S&W who made cylinders with huge throats. My early New-model Ruger Blackhawk had the same problem--.457 diameter throats and a .452 barrel.

I fought that thing for about ten years before I figured out what was wrong. FWIW, jacketed bullets will not upset enough to seal the chambers. I found this out when shooting a load of 20 gr of 2400 with either a 255 gr. cast bullet or the Hornady 250 gr. JHP. With the Hornady, I could see a huge fireball when I shot. With the LSWC, nothing. Finally figured out it was gas escaping around the jacketed bullet.

Factory .45 Colts had (and may still) a hollow base bullet that would expand to fill these huge bores. Maybe that had something to do with the factories decision to ream the cylinders so large.

 

[n4zov]

I bought a new M25 about 1980 or so and it was absolutely the most inaccurate handgun I have ever owned. It was even worse than the Grendel P10, and that is saying quite a lot! I tried everything from GI match ammo to 185 grain target ammo and I loaded at least two dozen bullet/powder combinations and bullets of three diameters. At 25 yards from a rest it would group into about 12" with a "good" load. At the same time, I had a Model 1950 target that would tear the x ring out of the target under the same conditions. I knew nothing about measuring cylinder and barrel dimensions, so I soon sold that piece of junk. Certainly S&W knew they were producing a handgun that was supposedly of target quality and did not even offer plinking accuracy. There was no excuse for producing a gun like that especially since S&W had previously produced almost identical guns that delivered superb accuracy. I learned from that experience that just because it has the Smith & Wesson logo stamped on it does not mean you are buying quality.

 

[Gun 4 Fun]

Factory .45 Colts had (and may still) a hollow base bullet that would expand to fill these huge bores. Maybe that had something to do with the factories decision to ream the cylinders so large.

Yes, factory loads still have the hollow based bullets, and they run .456" from Winchester, and .455" from Remington, the same as they have been from the beginning.

Remember, the original .45 Colt had a .454" bore, and did so until the mid 20th century, so ammo manufacturer's were using bullets that were slightly oversized until the bore size was standardized at .452" to go along with the .45 ACP's dimensions. However, the factories were reaming throats to accomodate the larger diameter bullets, and were extremely slow to get on board with cutting new reamers to the proper dimensions like they finally did at S&W when they went to the ABC 1234 serial system. I suppose that they were cutting reamers to around .457"-.458" to get possibly get more wear/use out of them, and as they wore down, the throats were still cut at .455"-.456"

It took a lot of complaining from customers to get them to do it even then, though they had known for quite some time that they had a problem.

S&W even offered to retrofit a new cylinder with the proper throats in any 25 that was sent back for quite a while once they got the throat issue under control. They no longer offer this service (though they will fit a new style cylinder/ratchet for a price).


What's worse, a lot of manufacturer's are still using oversized chamber reamers cut to maximum SAAMI specs that allow the case to bulge up just in front of the case head, which makes brass last nowhere near as long as it should, and causes difficult extraction at times, even with the anemic factory loads. I hear Ruger has finally addressed that, but they hadn't a couple years ago when I bought my last Blackhawk. I haven't really had an issue with that in my 25's, though I have in several older/early 29's.