TargetTalk

My wife is getting back into competitive shooting, and was doing quite well in the local NRA bullseye league until last Tuesday. Her groups suddenly opened up and were about 3 inches off center at 5:00. She is using a Docter red-dot sight, and I thought it might have gone wonky.

To make a long story short, it turns out that the barrel screw on her SP had loosened up. Not flopping around loose, but loose enough that the barrel must have shifted. The screw was still under a little tension, but I could easily tighen it a good half a turn or more. Unfortunately, I figured this out after she had switched to iron sights, re-zeroed the pistol and run out of time & ammo.

I was surprised A) that it came loose, and B) that the point of impact shifted that much. I haven't had time to check the manual, but I assume there is a lock washer of some sort inside. The pistol hadn't been cleaned in a while (~500 rounds), and was about due for a bath, at which time I would have caught it anyway.

I have several questions for any experienced SP shooters:

1) Has anyone else had this problem?

2) Any tricks to avoid it in the future? Tighten it every X rounds? Weak Locktite on the screw? New lockwasher?

3) Is it likely that shooting the pistol with the screw less than tight loosened things up? I'm still a bit freaked that the point of aim moved that much. If there is that much play, I'm surprised the thing doesn't need its sights tweaked after every cleaning. I haven't examined the "lock up" design to see where there is play when the screw is loose (or tight).

Thanks!

I have never experienced the barrel working it's way loose even after 500 plus rounds without a cleaning.

I have never used loctite either. It's been awhile since I took off the front plate which retains the barrel weights and springs but I do seem to remember that there is a washer on the barrel bolt somewhere. I think I have a parts diagram of the SP at home - please let me know you if you need it.

I think you might be onto something when you say the barrel may not have been tightened down snug enough on the last reasssembly which then made it possible to work itself really loose.

A group that moved three inches off center really isnt that much when you consider how much misalignment the front sight on even a mildly loose barrel can cause with the rear sight. I wouldnt have been surprised to hear the shots went off the paper.

I'm sure if you get it good and snug next time and have all the right parts, you wont see this happen again. If it does, Larry Carter at www.larrysguns.com is definitely the man to call.


Take care

I just re read your post and realized you have a Docter sight.

If it was mounted on the barrel just over the front sight post (as Don Nygord was fond of doing), then obviously a loose barrel should have made no difference.

On the other hand if you have a frame mounted Docter - even a slightly loose barrel would likely have disastrous effects on accuracy.

That's a new one---I have shot my SP & HP for several years now and clean them fairly often---never had that happen to me nor have I heard of it before. I use a "T" handle wrench with my Pardini's and mebbe it tightens better than a regular key.

I haven't run across that problem with my SPE, but on my old GSP that would happen. Can't say that I ever found a way of dealing with other than making sure it was tight when I took it out to shoot.

I received my SP1 electronic rapid fire in December 05, started shooting it in February, never took it apart or cleaned it. I have put well over 6000 rounds through it in the last month or so, no cleaning whatsoever, same battery in trigger. Screw has never loosened up. Just cleaned it last weekend. Screw was neither too tight or loose - it was just as it should be. Gun looks good as new.

Try an IZH 35m, where you have to tighten the shroud screws every 100 rounds - no exageration. That is my only complaint with the gun.

Jeff

I took the offending pistol apart last night. It really wasn't that dirty, and probably could have gone another 500 rounds before showing functioning problems. One thing I did find was that the steel insert that the barrel bolt goes into was also loose. That may have contributed to the problem. I tightened it up pretty good, but if it comes loose again, I will start by putting Locktite on the insert. I also cleaned most of the oil off the bolt and the threads in the insert so they would have a little more friction. That was how I found out the insert was loose. I screwed a cotton swab into it, and when I unscrwed the swab, the insert came with it.

As far as the lockup between the barrel & frame, there is a small steel pin in the frame that mates up with barrel. There's is a little play there, but I suspect that when you tighten the barrel screw, the barrel rotates a little until the play is taken up. This should give a fairly consistent position. However, if the screw loosens, the barrel CAN move a bit, which might explain a shift in point of impact. Because the barrel mounting system is short, I suppose a small error could produce a big shift on the target. It may be that the forces on the barrel from the slide tend to push it down & right if it comes loose.

By the way, the Docter sight mount I use is a German design that clamps on the rear dovetail, so a loose barrel will definitely mess things up.

Thanks for everone's input!