S&W 629 Accuracy Problem

[bwelch]

I have a super blackhawk that I've had now for 20+ yrs and shoot it very well. It's been "tweeked" a bit and shoots really great so I decided to start hunting with it several yrs ago. I put scope on it. It'll shoot a 3-4" group at 100 yds with factory ammo, semi jacketed hp. Like an idiot I decided I wanted a "new" gun a few months back so I bought a new S&W 629 Performance Center Compensated Hunter, put a Leupold VX3 2-8 scope on it with good Warne mounts and changed the trigger springs out to get it to a 2.5 pound pull. Its beautiful and has an awesome trigger, but I can not get a group at 100 yds better than 8-10" to save my life. And I consider myself a better than average pistol shooter. I have tried 6 different factory ammos that are running from 1120 fps up to 1365. Needless to say Im not happy with it. Any thoughts on what I might try?
Im wondering if I should slug the barrel, that maybe the barrel diameter is not .429 or .430. Maybe its very different than a Ruger.

[Cosmic_Charlie]

It should shoot as good as your BH. You better start taking some measurements. Maybe the forcing cone is tighter than the groove diameter.

[Drm50]

I have several 29-2s and a couple 24-3s and one old 3screw SBH. All good shooters. I have had
3 629s of various dashes and none of them shot groups. 629s are what turned me off of any
Stainless guns. I tried up to 431" and even as cast. Checked cone and cylinder throats, nothing
showing up there. Since I've had a couple more, don't shot them they go straight to trade pile.
I very seldom shoot anything but cast in S&Ws. I hunt with SBH with 240 JHP for near 50yrs

[arlon]

I recently got a new 625-8, it shot patterns. It was really bad with any jacketed factory ammo. Sent it to S&W, they sent it back with a replaced cylinder and about the same accuracy, maybe a little better but not much. I used the ram in a .452 lube/sizing die as a sort of pin gauge. I found three cylinders were similar and three were varying amounts tighter (one too tight to pass the pin). I used some 2000 grit paper and honed them slowly till they all felt about the same. It shot WAY better but still doesn't like any factory jacketed ammo I've tried in it. My cast is working fine now and that's all I wanted. I think getting a good cylinder on new S&W is a **** shoot. Some are fine but I had two stinkers in a row. Worth at least trying to check on that 629.

[Cosmic_Charlie]

It is disheartening to hear of all these lemons being turned out by Smith and Ruger. I guess if you have a shooter you better hang on to it. I'm picking up a new model 60 tomorrow and it had ****ed well better shoot good.

[Loudenboomer]

From your original post I can see you're not a stranger to magnum handguns. Please don't take this the wrong way. This is cheep and easy. Try concentrating on a consistent grip. It is a challenge to maintain a consistent hold especially when switching from one magnum format to another.

[murf205]

bewelch, you didn't say but are you a handloader? If so mic some of your jacketed bullets and see if they will push through the cylinder throats with finger pressure. Since it is a recent manufactured S&W, I'm thinking probably not going to go through. My gun had 3 cylinder throats that were .429 and 3 that were a tad bigger than .428. Get a cast boolit and slug the barrel. You really will not know where the problem is till you do some measuring. MY 629-8 was no tack driver either but I reamed the cyl throats to .431 and it helped a lot. You might want to get some pin gages to check your throats with. They are a valuable tool for us wheel gun junkies.

[bwelch]

I am a handloader and have several different CB's. What technique do you use to drive a CB down the barrel to slug it?

[Mal Paso]

Have you shot it without the scope?

[lazs]

I bought a used 629. 6.5" a 'classic' I bought it because the strength had been improved over the old model 29. I cast my own bullets and coat em with powder coat or Hi-Tek. I also own pin gauges. This gun is timed perfectly as best I can tell. all of the cylinder throats are just under .430 The bore is smooth and has no tight spots and runs almost exactly .429 I use a soft alloy push through slug from LBT for checking bores. it is not only important to check what the size of the bore is but also if there are any 'tight' spots. The LBT fire lapping compound is great for getting things right.

In any case.. this used gun had obviously not been fired much if at all. Everything checked out perfect and at the range with several handloads I was able to put most of my loads into around 1 1/2" at 25 yards from sandbags. This is about as good as I can shoot so I am very pleased. I use .430 and .431 cast and coated round nose flat points. At 100 yards I have not tried for groups. it is plinking range for us.. I know that I can hit a two liter bottle at least once or twice per cylinder with the gun tho. It is one of my more dependably accurate handguns

lazs

[bwelch]

Arlon,
Explain how you used the 2000 grit paper to hone the throats. Did you wrap it on something?

[bwelch]

Have you shot it without the scope?

I have not.
It shoots a 2-3" group at 40 yds. At 75 it shoots about a 6" and at 100 yds it spreads on out to 8-10". Not saying it couldn't be me or my grip but it does group consistent , just not good. Pretty much the same result every time I've been to the range. Probably have ran about 150 rounds through it.

[murf205]

I am a handloader and have several different CB's. What technique do you use to drive a CB down the barrel to slug it?

I run a patch of gun oil through the barrel and tap the nose of a boolit into the muzzle ALMOST all the way in with a plastic hammer. Then I use a 3/8" OAK dowel to finish driving the boolit through the other end. Lots of people say to use a brass rod but I haven't had any problems with the oak dowel rod. I put the barrel in my padded jaw vise and have some one hold it just in case.

[lazs]

I would be very happy with a 2-3" group at 40-50 yards but I have never owned a scoped handgun. it seems like yours is 'consistent' but not in a good way.. it should not double the size of the group every 25 yards in my opinion. Did you ever shoot your SBH at 25 yards? or at 50? My best groups with my 629 are all cast bullet loads. at 25 yards the jacketed seem to shoot about the same. it is difficult for me with open sights to get any load to shoot better than say an inch with one flyer opening it up to inch and a half say.

For me.. when a revolver shoots good at 25 but opens up really badly at say 50 yards it means that there is something wrong with the bore or throats. usually this can be fixed by shooting a thousand rounds of jacketed ammo (for the bore) or a few dozen firelap rounds. Almost any gun will improve in accuracy if it is fire lapped. From a little to a lot. If you have a tight spot (generally near the frame) then the bullet is squeezed down and then is undersized the rest of the way... but this works the same if the tight spot is anywhere except the muzzle... Pythons were actually bored with the muzzle being tighter than the rest of the barrel.

lazs

[Mal Paso]

Arlon,
Explain how you used the 2000 grit paper to hone the throats. Did you wrap it on something?

If you want accuracy send the cylinder to Doug Guy and have it reamed or get a Manson Reamer with the Pilots and do it yourself. You should have pin gauges first to know what dimensions you have. Machine marks are unimportant in the throat but the hole should be strait and true. Hand lapping can ruin that.

I have tried shooting full 44 Mag revolver from the Manson Rest and from bags and it was worse than offhand so I've no idea how you take the human factor out. My best 25y 6 shot group is 1 3/8" and Back when I went to the range every week I'd hit the x ring first shot half the time. I figure the gun would hit the same hole every time if I pointed it right.

629s are known for tight throats. Mine were around .428" and the groove was .429". I reamed the throats to .431" and shoot that size boolit. The gun was purchased used and the bubba trigger job failed so I bought a stoning fixture, cleaned up the sear and replaced he springs. It's had 2 1/4 lbs of reliable SA trigger for at least 50,000 rounds. Only thing is the trigger overtravel pin gets peened shorter so I don't try to keep it adjusted. Rambling LOL

My 629 bore is like a mirror, jacketed bullets will smooth a bore faster.

I like the Hogue Grips, they fit my hand and I can find the right hold without thinking but probably don't fit everyone.

That's all I Got.

[arlon]

Arlon,
Explain how you used the 2000 grit paper to hone the throats. Did you wrap it on something?

I just used a dowel stick, wrapped it with tape and added a few layers of 2000 grit we/dry at the end to get a close fit to the cyl.. No rocket science. Chucked the dowel into my cordless drill and took it very slow with a bit of oil until the pin felt the same as the looser cylinders felt.

[fast ronnie]

Honing should be done with a hone. Using sandpaper can (and probably will) make a tapered hole. No matter how careful. the ends will always cut differently than the center. Find someone who hones (not cut) valves guides, and chances are they may have the proper size mandrel. .429 would be an unusual size as most valve guides are not bigger than .375. Some machine shops will have a bench hone that might also have the correct mandrel.