CharlieT Posted May 22, 2007 Report Share Posted May 22, 2007 I'm not an engineer, just a humble keeper/farm worker so don't know much about threading barrels. Can anyone shed any light on the following. I gather that during the threading process the barreled action is held in a lathe and then the thread is formed, now my question is would it be possible that the barrel could be bent in the process of fixing the barreled action in the lathe. Charlie Quote Link to comment Share on other sites More sharing options...
Dunkield Posted May 22, 2007 Report Share Posted May 22, 2007 This is all getting a bit Inspector Morse now so how about this one... It was always bent, but came good again at the muzzle end. In chopping it the bit that corrected the skew was removed, exposing the bend for what it realy was along :( How about that one! or.. The barrel <should> have been turned between centres, and support at the muzzle end as you say Charlie, but at some point the muzzle was chopped this would (should) have done with a parting tool I would guess? a very narrow lathe tool, with the muzzle unsupported, again (??) I am going back to college/school days here, so it's a bit hazy as you can imagine Quote Link to comment Share on other sites More sharing options...
al4x Posted May 22, 2007 Report Share Posted May 22, 2007 but why is it shooting straight at 30 yards then and not at 50, surely if the bullet is going straight its going straight. Quote Link to comment Share on other sites More sharing options...
pin Posted May 22, 2007 Report Share Posted May 22, 2007 Edit: Simple answer is it isn't shooting straight at 30yds. Since it went away to be chopped the scope was removed. When it came back it needed to be re-zero'd so we wouldn't have noticed the fact that it wasn't shooting straight, we just zero'd it. We only noticed this behaviour when we moved further back, the bullet was always coming out and travelling left, but we compensated for this at 30yds by zeroing the scope, we had no reason to suspect we were actually compensating for a bent barrel. 50yds back the POI has moved as the bullet has more time to continue flying left instead of straight. Hope that makes sense, it did when I typed it Quote Link to comment Share on other sites More sharing options...
Dunkield Posted May 22, 2007 Report Share Posted May 22, 2007 Pin, Did SS shoot the gun at different distances before it was chopped? You may have just explained that of course Quote Link to comment Share on other sites More sharing options...
Graham M Posted May 22, 2007 Report Share Posted May 22, 2007 SS, If it shoots OK at 50 yards and shoots 25mm left at 30 that sounds pretty heavy. I have no idea what could cause that. Looking at it logically, we are saying the bullet path is curved :( I would suggest it is time to call in the big guns, have a word with GM,MRY, Devilishdave etc. Let us know how it goes. I had something similar on a .17hmr and couldn’t for the life of me figure it out, which is why I sold the damn thing to a dealer for PX. The only thing that does worry me when you get something like this is a crappy barrel where the obturation of the bore isn’t consistent. When the barrel is warm = one POI and when it’s cold = another POI. It looks like **** law and personally I would take it back to the shop and chop it in for another rifle I’m afraid. :yp: G.M. Quote Link to comment Share on other sites More sharing options...
dunganick Posted May 22, 2007 Report Share Posted May 22, 2007 im not going to get involved with this as im not sure of the problem, but the action screw has limited affect uppon the POI on this setup, all mine does is tighten and loosen the groups. btw are you chanigng the magnification or the paralax when moving between the positions, also have you floated the barrel correctly down hte r/h side, as cz's suffer from this problem. Also try shooting one group prone, getting up giving it a min and then shooting another group prone, just to see if the change in position and therefore pressure on the barrel through the bipod changes the POI. just another thought as well, do you have windage adjustable mounts? Quote Link to comment Share on other sites More sharing options...
pin Posted May 22, 2007 Report Share Posted May 22, 2007 Pin, Did SS shoot the gun at different distances before it was chopped? You may have just explained that of course Yeah, I personally didn't but I have seen him take close and further away rabbits with it and never heard him complain about this before. Quote Link to comment Share on other sites More sharing options...
Graham M Posted May 22, 2007 Report Share Posted May 22, 2007 Remember, some of the CZs do have a bit of choke in the end of the barrel and although it doesn’t affect the rifle 99% of the time, there will be the odd rifle that doesn’t like having this choke removed by being shortened. G.M. Quote Link to comment Share on other sites More sharing options...
CharlieT Posted May 22, 2007 Report Share Posted May 22, 2007 dunganik The reason I thought of the action screw was that CZ's stocks are tight on the right hand side, now if this one was particularly bad in this respect I thought that over-tightening the action may introduce a slight "bend" to the right which would mean it would shoot to the left. However I think I am clutching at straws ! GM Am I correct in thinking that the rifling process can introduce tension within the barrel and that in some cases chopping the barrel can cause this tension to be released thus making an inaccurate barrel. Charlie Quote Link to comment Share on other sites More sharing options...
dunganick Posted May 22, 2007 Report Share Posted May 22, 2007 dunganikThe reason I thought of the action screw was that CZ's stocks are tight on the right hand side, now if this one was particularly bad in this respect I thought that over-tightening the action may introduce a slight "bend" to the right which would mean it would shoot to the left. However I think I am clutching at straws ! Charlie all of the cz varmint stocks are simply machined poorly with the barrel channel slightly wonky. However most touch on the bottom anyway, so its not too much of a problem as they need opening up. Ticghtening the screw simply changes the frequency in the barrel, changing the accuracy in my guns case, not what cz intended but a useful design flaw. Quote Link to comment Share on other sites More sharing options...
Dunkield Posted May 22, 2007 Report Share Posted May 22, 2007 I want a 16" barrel for mine, I think I will do a 1-4-1 rather than having the end chopped off. My mate is just applying for a .22 FAC as well, bingo Quote Link to comment Share on other sites More sharing options...
bobt Posted May 22, 2007 Report Share Posted May 22, 2007 The best thing I ever did with my Brno was chop 8 inch off the end. well not me the gunsmith. Quote Link to comment Share on other sites More sharing options...
Stealth Stalker Posted May 22, 2007 Author Report Share Posted May 22, 2007 Cheers guys I think you've confirmed my worst fear, that the barrels bent :( It certainly wasn't before the chop, I'm going out with the peltman 2moro for a final verdict before it goes back to the gun shop. Thanks all that replied I'll keep you informed. SS Quote Link to comment Share on other sites More sharing options...
MilDot Posted May 22, 2007 Report Share Posted May 22, 2007 try different mounts for the scope. I have a feeling that the centre of the scope isnt pointing in a straight line with th ebarrel. Ie the scope is pointing say to the left so as you move ranges so the scope is pionting further 1 way than the other. Similar to the trajectory of the bullet but horizontal not verticaly. Does that make sense! I know what i mean.... lol Quote Link to comment Share on other sites More sharing options...
the pelt man Posted May 23, 2007 Report Share Posted May 23, 2007 Hi SS Further to what Mildot has said, check the mount shells is there a even gap left and right of the top shell to the shell of the base, The scope (as Mildot says) could be running slightly to the left of the centre line. This could be caused by the front mount top shell being tightened right down on the right side with a gap between top shell and the base of the mount on the left and the opposite with the back mount. Hope this makes sence. When you pull the cross hair across to 30yard POI your zero will be out at 50yards PELTMAN Quote Link to comment Share on other sites More sharing options...
Stealth Stalker Posted May 23, 2007 Author Report Share Posted May 23, 2007 Well after gearing myself up in front of the mirror for an argument (possibly fisticuffs) if it came to it , down at the gun shop :( The Peltman took one look at the scope, called me a "silly man" or words to that effect & pointed out that the scope rings were tightened irregularly, pretty much how he described in the previous post. The front ring had a 1.5 mm gap on the left srews & a .5mm gap on the right between the mount The back ring had a 1.5mm gap on the right screws & a .5mm gap on the left between the mount, causing the scope to be kind of twisting. He loosened them off and tightened them back properly, BINGO problem sorted :( we tried it at 30,50,60 & 70 yds no creeping left or right. I feel a complete **** not noticing this before :yp: And to think Pin & me put about 300 shots through it trying to sort the problem at least it was nothing serious like a bent barrel :( Many thanks Pelty :( & thanks to everyone else who helped out Cheers SS :look: Quote Link to comment Share on other sites More sharing options...
Dunkield Posted May 23, 2007 Report Share Posted May 23, 2007 I feel a complete **** not noticing this before :( Always look for the positives SS. At least you put it back on the right way round The bunnies will peobably be slightly less happy you are now sorted :yp: Quote Link to comment Share on other sites More sharing options...
the pelt man Posted May 23, 2007 Report Share Posted May 23, 2007 I feel a complete **** not noticing this before :( Always look for the positives SS. At least you put it back on the right way round After giving it a go i'm not so sure it is on the right way :look: Give me my WTC 6.5-20x50 any day PELTMAN :yp: Quote Link to comment Share on other sites More sharing options...
CharlieT Posted May 23, 2007 Report Share Posted May 23, 2007 Who is this PELT MAN...............he's a clever little ****** Well done mate Charlie Quote Link to comment Share on other sites More sharing options...
Stealth Stalker Posted May 23, 2007 Author Report Share Posted May 23, 2007 I feel a complete **** not noticing this before :( Always look for the positives SS. At least you put it back on the right way round :( After giving it a go i'm not so sure it is on the right way Give me my WTC 6.5-20x50 any day PELTMAN :yp: You need your eyes tested mate, nowt wrong with the scope, as you may recall it was me that pointed out that the scope cover was still on :( :look: Let me at them pesky wabbits, now lets see which way round do I hold this pesky rifle :( SS Quote Link to comment Share on other sites More sharing options...
pin Posted May 23, 2007 Report Share Posted May 23, 2007 All I know is don't ask me, because I never spotted it either. I asked about it but never checked Cheers **** #2 :( Quote Link to comment Share on other sites More sharing options...
kip270 Posted May 23, 2007 Report Share Posted May 23, 2007 Well done Peltman :( Quote Link to comment Share on other sites More sharing options...
the pelt man Posted May 23, 2007 Report Share Posted May 23, 2007 I feel a complete **** not noticing this before Always look for the positives SS. At least you put it back on the right way round After giving it a go i'm not so sure it is on the right way Give me my WTC 6.5-20x50 any day PELTMAN You need your eyes tested mate, nowt wrong with the scope, as you may recall it was me that pointed out that the scope cover was still on :D Let me at them pesky wabbits, now lets see which way round do I hold this pesky rifle SS Thats it the gloves are off, This is the guy who wants to zero his gun to 60 yards so brings a "METRIC" tape with him PELTMAN Quote Link to comment Share on other sites More sharing options...
al4x Posted May 24, 2007 Report Share Posted May 24, 2007 Game set and match Quote Link to comment Share on other sites More sharing options...
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