New 625-JM questions

[CW White]

Just bought a new S&W 625-JM. I have been to the range and after about 200 mild .45AR rounds through it I and a couple of my friends are generally very pleased. HOWEVER, there are 2 things that bother me.

-on the cylinder, the star wheel ejector is nicely chamfered or radiused, but the cylinder side of each cylinder remains square. I thought each cylinder was supposed to be completely radiused.

-the forcing cone end of the barrel seems to have been final ground to length and a very sharp burr (can cut while cleaning) exists around the whole open side of the barrel.

Are these normal things you live with with a S&W, or should I contact the company.

Any input from other owners pf 625 JC or experienced S&W owners is appreciated.

 

[tomcatt51]

That's how it is. Deburr the barrel edges (carefully) with a fine file and have the chambers chamfered. If you're shooting reloads you'll probably want the chambers reamed also. They tend to be enough undersize that you can have chambering problems with resized brass.

 

[johngalt]

My 625JM has burrs around the outside of the diameter of the forcing cone. Functionally it makes no difference, so I haven't done anything. It just looks a little sloppy.

My chambers are a little tight though. Federal brass (which seems to be thicker than most) won't chamber. Winchester and Remington are fine though. I'm a little hesitant about having the chambers reamed, because I've read that the chamber throats are critical for accuracy and I don't want to ruin the cylinder.

 

[TSQUARED]

That's the way they have been coming out during the past few years. They may not be as appealing cosmetically but they still shoot perfectly well.

 

[tomcatt51]

My chambers are a little tight though. Federal brass (which seems to be thicker than most) won't chamber. Winchester and Remington are fine though. I'm a little hesitant about having the chambers reamed, because I've read that the chamber throats are critical for accuracy and I don't want to ruin the cylinder.

Tight (undersize and out of round) chambers are very common on 625-8's. A chamber finish reamer (I have one and have reamed and chamfered a number of 625 cylinders) will cut the chamber but NOT the throats. It pilots in the throat. To ream the throats (very rarely necessary in 625's) you use a different reamer.

 

[Tom C]

Tight (undersize and out of round) chambers are very common on 625-8's. A chamber finish reamer (I have one and have reamed and chamfered a number of 625 cylinders) will cut the chamber but NOT the throats. It pilots in the throat. To ream the throats (very rarely necessary in 625's) you use a different reamer.

I haven't noticed the chambers are out of round, but the forcing cone of my 625JM was so rough it looked like it was cut with a pen knife. I was able to recut it with a 5 degree forcing cone reamer from Brownell's. The throats are nice and tight and it now shoots very well. It also needed some internal smoothing to get the trigger action the way I want it, and I also had to take the edge off the trigger serrations or it would tear up my trigger finger. It is now very nice, but I now have a 625PC. It is just a touch lighter, and a little lighter in the muzzle and at the moment I prefer it to the JM. While I smoothed up the internals of the PC just a little, I didn't have to recut the forcing cone or anything else like that.

 

[tomcatt51]

I haven't noticed the chambers are out of round,

You won't really "notice" them being out of round, it just contributes to the undersize problem. Some I checked while figuring out what was going on were .004" out of round, checked with a telescoping gauge and a micrometer. It's very "noticeable" as you ream them.

 

[Tom C]

You won't really "notice" them being out of round, it just contributes to the undersize problem. Some I checked while figuring out what was going on were .004" out of round, checked with a telescoping gauge and a micrometer. It's very "noticeable" as you ream them.

I have a good digital inside mic and I will check them this weekend.

 

[tomcatt51]

I have a good digital inside mic and I will check them this weekend.

Will be interesting to see what you find. I don't check them anymore, just ream them. The only one I've found where the reamer didn't remove metal was a -3 that the reamer (std finish reamer) just rattled around in. The chambers were HUGE but had not been chamfered, I don't know who or what had been done to it. 625-2's were actually "recalled" to have undersize chambers fixed.

 

[scooter123]

If it's a 625 JM made this year, say August or later, I'll be very surprized if you find any issues with the chambers. Mine was test fired August 11, 2011 and the chambers in the cylinder had such a perfect finish I suspect that S&W is now using the ECM process to machine the cambers to size. Quite simply there were NO tool marks visible even under magnification.

BTW, my extractor was also chamfered and the chambers were not. That I addressed with a diamond burr on a Dremel using the chamfer on the extractor as a guide, all told it took about 40 minutes.

 

[tomcatt51]

I'll be very surprized if you find any issues with the chambers. Mine was test fired August 11, 2011 and the chambers in the cylinder had such a perfect finish I suspect that S&W is now using the ECM process to machine the cambers to size. Quite simply there were NO tool marks visible even under magnification.

What does the chambers surface finish have to do with their size? Having a nice surface finish doesn't negate them being undersize. Read post #3, second paragraph.

 

[scooter123]

What does the chambers surface finish have to do with their size? Having a nice surface finish doesn't negate them being undersize. Read post #3, second paragraph.

It's an indication that S&W may be changing manufacturing processes to a more repeatable process. If they are using the ECM process to machine the chambers it's then simply a matter of them setting the process up to the correct size, tool wear would no longer come into play.

BTW, I've been around machine shops since the 70's and I have NEVER seen a machined surface this clean, honing, lapping, and reaming all leave some small trace of a circular machining method and they are NOT present in the cylinder on my 625 even under magnification.

While it's not as accurate as using pin gages to check the chambers, I did just measure 15 of my fired casings and all checked at 0.472-0.473 inch in diameter, and indication that sizing is consistent. I also used the ID jaws on my calipers to measure the chambers and they check at 0.475 inch, however that is NOT a preferred method for measuring an ID. Also took an unfired round that measured at 0.474 inch at the base and inserted it backwards in the chambers and it slips freely in all chambers. Based on all of this I expect the chambers will pin out between 0.475 and 0.476 inch. Whether that is ideal for the 45 ACP I do not know, however on my 625 the chambers check quite consistent using my improvised methods and I've not had one single issue with the cylinder.

BTW, one issue I do have is a cocked barrel, something I'll be addressing in the next month when I crown the barrel and lap the forcing cone. Been wanting to do a full on accurized revolver and the cocked barrel has provided a good "excuse" to purchase a frame wrench and do it.

 

[tomcatt51]

If you're shooting factory ammo you're usually, but not always, ok. Once again, read post #3. I ran into big problems with brass fired in my 1911 (many times) because the semi-auto's bigger chambers had allowed the brass to swell more near the base and many re-sizing dies don't adequately re-size this area.

FWIW my reamed chambers measure (actually measured with a telescoping gauge and verniered micrometer) .4800 - .4802 checked just past the ejector. Fired brass runs .475.

One gun does not a good sampling make, just like shooting 6 shot groups and counting only the closest 4 does not make for meaningfull accuracy testing.

 

[Tom C]

Will be interesting to see what you find. I don't check them anymore, just ream them. The only one I've found where the reamer didn't remove metal was a -3 that the reamer (std finish reamer) just rattled around in. The chambers were HUGE but had not been chamfered, I don't know who or what had been done to it. 625-2's were actually "recalled" to have undersize chambers fixed.

I measured my 625JM, 625PC, 25-2 and a Ruger NMBH with .45 ACP cylinder. I had to average the numbers due to my not terribly consistent measuring technique.
…………......……25-2…... 625JM.…..625 PC…. .45 NMBH
Chamber:...47993"…..47837"…..47818"…..48058"
Throats:…..45633"…..45229"…..45201"…..45270"
Chambers are pretty close. Throats of JM, PC and NMBH are close, but the 25-2 is pretty huge. The old 25-2 originally had poor chamber alignment. After finally getting that fixed, it shoots very well. The JM had the rough forcing cone. It has been corrected and it shoots well. The PC shot well from the start. The NMBH has had tight chamber throats reamed to a nominal .4525". You would need a Ransom Rest to quantify differences in accuracy. I strongly suspect the 25-2 shoots well because the .45 ACP or AR case is so small in relation to the LP primer that the nearly square pressure wave of the primer puts the bullet into the forcing cone before the pressure wave of the powder catches up with it. It doesn't have time for blow-by, therefore it can get by with larger throats than would work for a larger case.

 

[tomcatt51]

Not bad. The 25-2 throats are typical. What measuring the chambers doesn't tell is how round and straight they are. Reaming them in increments and looking at where you're cutting metal really shows that. I measured my 45 acp reloads, 250 gr RNF, that have been run thru a Lee FCD because the bullet is a .45 LC bullet crimped in it's groove and was leaving a "ring" on the case at the bullet base. .470 just above the extracator groove, almost .473 at the "ring", ~.470 near the mouth. .478 chambers would probably be ok if they were straight and round (and clean), many don't seem to be and when you're dropping in 6 rds at a time with moonclips and expecting them to fall in it's easy to have a problem.

 

[scooter123]

If you're shooting factory ammo you're usually, but not always, ok. Once again, read post #3. I ran into big problems with brass fired in my 1911 (many times) because the semi-auto's bigger chambers had allowed the brass to swell more near the base and many re-sizing dies don't adequately re-size this area.

FWIW my reamed chambers measure (actually measured with a telescoping gauge and verniered micrometer) .4800 - .4802 checked just past the ejector. Fired brass runs .475.

One gun does not a good sampling make, just like shooting 6 shot groups and counting only the closest 4 does not make for meaningfull accuracy testing.

Your post remined me that I had a set of telescoping gages out in the garage, haven't used them since I put an engine together back in 2000.
Unfortunately, the good mics are at work so all I have are my Mitotoya calipers I keep at home.

Chambers measure slightly tapered, 0.479 inches 1/8 inch down and 0.475 inch at the bottom. Don't know if those are ideal dimensions and these calipers don't read in 10ths. However according to the specs for the 45 ACP in Wikipedia the casings are supposed to be 12.09 [.4760] and 12.02 [.4732] at base and top. Since I don't have a 1911 that was poorly throated I don't see any need to fool with the chambers on my 625.

In addition, if S&W is using ECM to machine the cylinders it's quite likely that just one sample may be indicative. I have yet to see one single complaint about the ECM barrels being either over or undersized. Unlike the complaints about problems with broached barrels that are machined, the ECM process appears to be free of issues related to tool wear or improper coolant flow.

 

[tomcatt51]

I don't see any need to fool with the chambers on my 625.

If the ammo you're buying chambers ok then they're fine for the purpose. Some of us reload and shoot competitively in events with "on the clock" reloads. In that context they're frequently not "good enough".

 

[Tom C]

Tight chambers maximize accuracy, but looser chambers are really nice for fast reloads and loose very little accuracy. Gaging your reloads also helps.

 

[scooter123]

If the ammo you're buying chambers ok then they're fine for the purpose. Some of us reload and shoot competitively in events with "on the clock" reloads. In that context they're frequently not "good enough".

Wouldn't segragating your brass provide a solution? I'm not a reloader so it's a serious question. I'd think that if you had a 625 with chambers on the small side of the specification you should be able to continue to use that ammo in the 625 without issues.

 

[tomcatt51]

Wouldn't segragating your brass provide a solution? I'm not a reloader so it's a serious question. I'd think that if you had a 625 with chambers on the small side of the specification you should be able to continue to use that ammo in the 625 without issues.

Fair question. My brass is all Federal now. Once fired (in a semi-auto) LE brass that gets sized in a separate step in a Lee sizing die (sizes the brass farther down near the extractor groove) before getting loaded in a Dillon Square Deal B and checked in a TKCustom moonclip checker Welcome to TK Custom.com & Moonclips.com. My 250 gr USPSA loads get run thru a LEE FCD also as a last step before the checker. Having brass being fired only in the revolver helps as does the separate sizing step but reaming the chambers is also pretty much necessary. I'm not the only one, this is a std thing for 625's set up for USPSA revolver or ICORE or IDPA etc. Along with a usually 5 to 6 lb DA trigger. I've seen no downside to reaming the chambers, they're not being "hogged out" oversize, they're being reamed with a SAAMI spec finish reamer and being made the size they should have been to start with.

 

[scooter123]

Using my google-fu, which seems to uncommonly effective for me tonight, I actually located the SAAMI specification drawings for the 45 ACP. While I concede that digital calipers aren't the best choice for measuring the chambers it would appear that the chambers in my 625 are pretty much dead on to specification.

It may be another indication that S&W has been refining their manufacturing processes to eliminate some of the issues we've seen in regards to quality. Now if they would just provide a fixture to the blind monkey mounting the barrels we just might see the number one complaint become history.

Following is a link to that document. BTW, you'll find both cartridge and chamber specs on page 49.

http://www.saami.org/specifications_and_information/publications/download/205.pdf

 

[Tom C]

Fair question. My brass is all Federal now. Once fired (in a semi-auto) LE brass that gets sized in a separate step in a Lee sizing die (sizes the brass farther down near the extractor groove) before getting loaded in a Dillon Square Deal B and checked in a TKCustom moonclip checker Welcome to TK Custom.com & Moonclips.com. My 250 gr USPSA loads get run thru a LEE FCD also as a last step before the checker. Having brass being fired only in the revolver helps as does the separate sizing step but reaming the chambers is also pretty much necessary. I'm not the only one, this is a std thing for 625's set up for USPSA revolver or ICORE or IDPA etc. Along with a usually 5 to 6 lb DA trigger. I've seen no downside to reaming the chambers, they're not being "hogged out" oversize, they're being reamed with a SAAMI spec finish reamer and being made the size they should have been to start with.

Could you provide some information on the chamber finish reamers? I looked in Brownell's at Clymer and Manson reamers, but it wasn't clear which was the one with pilot for revolvers.

 

[tomcatt51]

Could you provide some information on the chamber finish reamers?

PISTOL CHAMBERING REAMERS - Brownells
The one I have is the 184-051-450. Make sure you use a good cutting oil.
I use Brownells piloted 45 degree chamfer cutter for the chamber chamfers. The pilot usually won't fit in the chambers until they're reamed.

If you have a 617 (or 17) the Manson chamber reamer is 513-051-220. They benefit greatly from reamiming the chambers.

 

[tomcatt51]

While I concede that digital calipers aren't the best choice for measuring the chambers it would appear that the chambers in my 625 are pretty much dead on to specification.

It may be another indication that S&W has been refining their manufacturing processes to eliminate some of the issues we've seen in regards to quality. Following is a link to that document. BTW, you'll find both cartridge and chamber specs on page 49.

Thx, I'd looked for saami specs and hadn't found them. I'd say the reamed chamber is right on nominal spec. (at least the areas the reamer cut, there were small areas it did not cut) and I agree calipers are not a suitable measuring implement.

S&W may be doing better. They may be closer in terms of size but if they're any straighter is more difficult to determine. Want to find out? For the sake of arguement I'll ream your chambers for the price of return shipping (assuming my .452, measures .4515, pilot will fit your throats). I'll save the chips and return them with the cylinder. PM me if you're interested.