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Post by 2 Dogs on Apr 13, 2012 14:35:12 GMT -5
I recently purchased a Smith and Wesson 625 PC 4" 45 acp/AR. This should be a match grade absolute treasure and pleasure to shoot. However, this one is about minute of pie plate. The best loads so far are 185 grain JHPs which group about 3" or so at 25 yards. Most cast loads will stay on a pie plate but man it's UGLY. This all happens for a reason, not the least of which a shooter may be shooting ammo that doesnt fit his sixgun properly. Time to take it back to the shop, clean it up, and do some measuring. In this case, the cylinder mouths are a uniform .4525" which is very nice. I might also add that this gun has the shoulder properly cut into the chambers so you can shoot it without moon clips if you need to and just cuz thats the way they should be cut. Measureing the barrel is where we run into trouble. A .441" pin gauge will fall all the way thru but a .442" will stick right in the middle of the barrel. So, this particular barrel is a blunderbuss. That is, bigger at the muzzle than at the throat end. Totally unproper, and not very useful for best accuracy. At this point some firelapping is in order. Since the restriction in this case is likely less than .001" I am going to try to lap it out with the standard grit and hope for the best here. The photo here shows the prepped cases, lapping compound and kit, Smith 625PC, and some lapping bullets. Remember to use your cylinder as a gauge when selecting cases to use for lapping. They should be polished but fired and unsized and a slip fit.
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Post by hammerdown77 on Apr 13, 2012 15:15:42 GMT -5
I know it goes against the DIY nature of this forum and its members, but did you try calling Smith to have them put a new barrel on the gun as a warranty repair? Or will you try that if the lapping fails to produce the desired accuracy?
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Post by 2 Dogs on Apr 13, 2012 18:57:10 GMT -5
I'm kinda curious why one could think Smith or any other major manufacturer would know or even understand the difference? I'm not trying to be sarcastic here at all. The simple fact as stated before is that no matter who makes the barrel, yes even the customs, it may have restriction in the bore. If one wants good accuracy with cast, good dimensions certainly help. Stainless in my experience is quite the pain to fire lap.
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Post by majorKAP on Apr 13, 2012 19:04:37 GMT -5
I like great big bolts.
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Post by agrizz on Apr 13, 2012 19:06:39 GMT -5
I had a Smith 25-5 a number of years back and it would not shoot very well. I thought I would shoot silhouettes with it. Well after shooting it and not hitting pie plates at 40 yards I checked it out on a piece of inspection equipment called a SIP. And I ran a check for cylinder run out and chamber location as well as crane location to the center of the barrel. After the casts of the barrel and cylinder were made the results were. Cylinder throat at .4522 to .4525. The barrel however had a groove diameter of .458 on the nose with a 454 forcing cone. This had a hi thread compression on the barrel.
I returned it to Smith with this information included and the fact that it was not shooting very well due to these issues with the barrel. 2 weeks later It was returned to me with a letter from the Smith repair center stating that this was the normal manufacturing tolerance for this gun. This was not the first issue I had with Smith but this was a prime example. I love the way a Smith handles and the way they look. Will I ever purchase another Smith? Not on your life.
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Post by 2 Dogs on Apr 13, 2012 20:03:33 GMT -5
Nels, today being Friday the 13th, I thought I would relate some unexpected things I have learned about my sixguns and how no matter how much you think you know what you are doing why you should NEVER skip a step. So, I sat down to reload some lap bullets. 3.5 grains of 231 was the charge I selected. I rolled my bullets as usual in the lapping grit and got all set up to seat them. Instead of seating one and chamber checking it, I went ahead and seated them all. Hey, Im an expert right??? Done this firelapping thing many times. I know what Im doing..... My error was forgetting the 45 acp case is tapered toward the center on the inside. So when I seated my bullets all the way to the mouth of the case, it caused just enough bulge in the case to keep them from chambering in my Smith properly. Hmmm. Rule #1 of loading ammo: Your cylinder makes a wonderful case gauge, IF you use it!! Knucklehead. Dunce. Expert my ASS! I had made 48 firelap rounds and considered taking them all apart. The one tool I HATE the most on my bench is my intertia bullet puller. I have 3. Im an EXPERT remember? I have 3 45 ACP revolvers at my house. Said Smith 625, A Ruger 5.5" Harton Blackhawk, and a Factory tuned FA97. Now here is where things get interesting. I pulled my Ruger 45 acp cylinder and started to check these rounds. 30 of them fit nicely. Hmmm, that Smith has tighter chambers than the Ruger. Now here is where all this gets interesting.... On a whim I pulled my 45 acp cylinder out of my FA97. Almost all the other rounds that wouldnt fit in either the Smith or the Ruger fit in the FA. Measuring my FA cylinder against my Smith cylinder shows my Smith cylinder to be almost .004" tighter!!! Now who would have thunk it? Use your cylinder as a case gauge. Always check everything.... Tomorrow I get to start over!!!
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Post by shooting4life on Apr 13, 2012 20:03:57 GMT -5
If you have to return it don't mention the fire lapping.
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Post by hammerdown77 on Apr 13, 2012 20:26:31 GMT -5
So does where the restriction lies in the barrel make a difference? You say that customs and such may have restrictions in the barrel. Do they shoot better than this PC Smith? I would hope so. I have a couple of Rugers with restrictions in the bore, one at the frame and the other at the frame and the roll marks. Accuracy is better than what you are describing with that Smith. Just wondering if something else is also contributing, and if it's not worth trying to "fix" that barrel.
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Post by 2 Dogs on Apr 13, 2012 20:35:45 GMT -5
Yes it does. The barrel should choke down towards the muzzle. I dont "say" that customs and such "may" have restriction, I KNOW it. Here is an article I wrote on the subject, including pics of high end customs with less than perfect barrels: www.gunblast.com/FerminGarza-Firelapping.htm
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Post by hammerdown77 on Apr 13, 2012 21:14:45 GMT -5
Yes, I've read that article before. I did not mean to imply that you didn't know that they had restrictions. Poor choice of words on my part.
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Post by hoover on Apr 13, 2012 21:23:21 GMT -5
Roll stamping will constrict a perfect barrel......
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Post by agrizz on Apr 13, 2012 22:37:57 GMT -5
2 Dogs I pulled about the same kind of a stunt however it was with, a new to me, about 1984 Freedom Arms 454. The issue I had was a crimp that was too heavy and bulged the case enough that they would not chamber. Bullet puller and 20 rounds later I was back in business.
The different companies and equipment that these guns are made on allow for these different dimentions on a cylinder. There are tolerances that are accepted in the industry for all metal working and are a plus and minus factor. The same case may fit in a plus sized chamber because the chamber is oversized and not in a minus sized chamber because it is on the low side of the tolerance range.
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Post by subsonic on Apr 13, 2012 23:00:20 GMT -5
I didn't say this, but a gentle tap from a rawhide mallet will probably get them into the chambers.
Just don't hit the primers and don't bend the crane.
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Post by boxhead on Apr 14, 2012 15:11:09 GMT -5
I'd send it to S&W under warranty. Nothing to loose and with a clear explanation prior to shipment I suspect they will fix the problem with little to no cost. At least that was my experience with M25-5 with chamber and throat issues. The guns shoots very well now with proper throats and the old cylinder has been put to use by my wife in her office.
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Post by 2 Dogs on Apr 14, 2012 15:33:05 GMT -5
Every once in a while a project will just take on a life of its own. I built some new firelap loads this morning for the 625PC. Normally I would scorch ole Subsonic for his comment above, except for the painful fact that he is right in this case. My firelap bullets are .453s and my throats are .4525, so normally a .453 bullet will be a nice press fit. Well, except when you roll it around in lapping compound. Then it is just a bit snug and needed a bit of extra urging to seat. I firelapped the 625PC a bit over 40 rounds. My Harton Ruger Bisley (which had NO restriction) about 30 rounds just to polish the bore a bit and for good measure. AND last, my FA97, which now has some 230 or so of firelap loads thru it (that FA steel is HARD).
The groups with the Smith improved quite a bit. It would be hard to say how much as the winds outside were gusting to 40+ MPH which makes shooting your best groups quite difficult. But I can see that it is better. I shot some stout 45AR reloads in it and after 3 cylinders could still see some leading so while I am closer, I am not there yet. Cleaning and remeasuring the barrel showed that now a .442" pin gauge slipped all the way down with no problems, BUT, now a .443 will just barely start in the muzzle.
The Ruger almost immediately began to stack the firelap loads so that one is good to go. The FA, still shows some restriction in the barrel right behind the front sight.
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