wheelybins Posted July 13, 2012 Report Share Posted July 13, 2012 Hi all. I have a CZ ZKM452 American in .17 HMR. It has been very erratic ever since new. It is fitted with a SAK mod and I am using Winchester 17gr V-max ammo. With the mod on it will group 8 inches at 100yds at best. I have replaced the mod with a new one the same and got exactly the same problem. Without the mod it shoots 0.5 inch groups all day long. I have looked at both mods and they are not damaged in any way. Does anyone have any idea what is going on? Cheers. Graham Link to comment Share on other sites More sharing options...
Gaz Posted July 13, 2012 Report Share Posted July 13, 2012 Just a guess , have you checked the thread on which the mod is fitted to ,was it factory threaded or did you get it done elsewhere ? Cheers gaz Link to comment Share on other sites More sharing options...
wheelybins Posted July 13, 2012 Author Report Share Posted July 13, 2012 Just a guess , have you checked the thread on which the mod is fitted to ,was it factory threaded or did you get it done elsewhere ? Cheers gaz The thread looks perfect, and was factory done. Cheers Link to comment Share on other sites More sharing options...
bri2506 Posted July 13, 2012 Report Share Posted July 13, 2012 It's probably touching on the stock with mod on. I packed mine up on bridge with some thin plastic. Or it might just be touching where the sling fasten to, might just want a rub with a bit of sand paper Link to comment Share on other sites More sharing options...
wheelybins Posted July 13, 2012 Author Report Share Posted July 13, 2012 It's probably touching on the stock with mod on. I packed mine up on bridge with some thin plastic. Or it might just be touching where the sling fasten to, might just want a rub with a bit of sand paper Good thought, I'll check that. Thanks Link to comment Share on other sites More sharing options...
hughes.s Posted July 13, 2012 Report Share Posted July 13, 2012 I had problem with grouping I purchased the rifle with the mod fitted, the problem was whoever had threaded the barrel, had damaged the crown, and the thread looked as if had been cut with a blunt pen knife. I took it back to the shop and they recrowned and tidied up the thread, it was ok after that. Hughes.s Link to comment Share on other sites More sharing options...
triggersqueezer Posted July 13, 2012 Report Share Posted July 13, 2012 i had a bad datch of winchester wich wont help try a box of hornady. Link to comment Share on other sites More sharing options...
wheelybins Posted July 13, 2012 Author Report Share Posted July 13, 2012 i had a bad datch of winchester wich wont help try a box of hornady. I did wonder about it being a bad batch of ammo, but I figured it wasn't that because it shoots so well without the mod. I'm confused!!! Graham Link to comment Share on other sites More sharing options...
tackb Posted July 13, 2012 Report Share Posted July 13, 2012 theres only a couple of things it can be , the weight of the mod is affecting the free floating or the mod is fouling the bullets ? as long as it shoots well with out the mod? Link to comment Share on other sites More sharing options...
wheelybins Posted July 13, 2012 Author Report Share Posted July 13, 2012 theres only a couple of things it can be , the weight of the mod is affecting the free floating or the mod is fouling the bullets ? as long as it shoots well with out the mod? Fair point It is just a bit too loud without the mod. I went back to my .22 but that really does seem like a pea shooter now. Cheers Link to comment Share on other sites More sharing options...
Tank Posted July 13, 2012 Report Share Posted July 13, 2012 sames as the others have said. It can only be that the barrel is not fully floated,the threads or crown are knackered or that the ammo is not a match for your rifle? I use CCI 17grain hollow points but it will shoot the hornady in nice groups too. I had to free float mine to the extent I could get a piece of thick paper running all the way along between the barrel and the stock. Not had any problems since. Link to comment Share on other sites More sharing options...
wheelybins Posted July 13, 2012 Author Report Share Posted July 13, 2012 Does anybody have an opinion on whether SAK mods are any good? I did wonder if that might be something to do with it. Cheers Link to comment Share on other sites More sharing options...
tikkajohn Posted July 13, 2012 Report Share Posted July 13, 2012 Does anybody have an opinion on whether SAK mods are any good? I did wonder if that might be something to do with it. Cheers As you say its printing 1/2" without the mod, The cause of the inaccuracy IS related to the mod in some way. I would free float the stock first I done this with mine and it tightened the groups. Then If this doesnt work try a different mod and finally if all else fails it probably needs rethreading. ATB John Link to comment Share on other sites More sharing options...
wheelybins Posted July 13, 2012 Author Report Share Posted July 13, 2012 As you say its printing 1/2" without the mod, The cause of the inaccuracy IS related to the mod in some way. I would free float the stock first I done this with mine and it tightened the groups. Then If this doesnt work try a different mod and finally if all else fails it probably needs rethreading. ATB John That all sounds sensible. It is much frustrating though, it's the only rifle that I own that doesn't shoot straight Cheers Link to comment Share on other sites More sharing options...
happyhunter Posted July 13, 2012 Report Share Posted July 13, 2012 Hi all. I have a CZ ZKM452 American in .17 HMR. It has been very erratic ever since new. It is fitted with a SAK mod and I am using Winchester 17gr V-max ammo. With the mod on it will group 8 inches at 100yds at best. I have replaced the mod with a new one the same and got exactly the same problem. Without the mod it shoots 0.5 inch groups all day long. I have looked at both mods and they are not damaged in any way. Does anyone have any idea what is going on? Cheers. Graham Had exactly the same problem with the thumbhole 455, took it to bits and with a bit of copper pipe with wet and dry wrapped around i sanded out the barrel channel in the stock and he presto the problem disappeared! Had it for the nv but sold it for a .223 with a bit more knock down power! Hope this helps. Link to comment Share on other sites More sharing options...
sako Posted July 13, 2012 Report Share Posted July 13, 2012 Just a guess , have you checked the thread on which the mod is fitted to ,was it factory threaded or did you get it done elsewhere ? Cheers gaz This is where the problem is the thread on which the mod is fitted to ! without mod ,and try another mod,you remove the problem. my mate had same issue with a .17hmr browning t bolt,the shop put it in with a smith, now it shoots ok Link to comment Share on other sites More sharing options...
dorg Posted July 13, 2012 Report Share Posted July 13, 2012 We have played with most mods and for the money you cant beat the Saks Link to comment Share on other sites More sharing options...
kingsburyshot Posted July 13, 2012 Report Share Posted July 13, 2012 try one of the old style parker hale mods works a treat on my .17 Link to comment Share on other sites More sharing options...
Tank Posted July 14, 2012 Report Share Posted July 14, 2012 I've got the wildcat whisper, very well made, moderates well and looks good. If you've got the money that or the DM80 are lovely mods. Maybe try One less charlie on here, he makes mods. Link to comment Share on other sites More sharing options...
Si-Snipe Posted July 15, 2012 Report Share Posted July 15, 2012 If you are getting good consistent groups without the mod then it's got to be the mod as somone already stated. Can you look inside the mod to see if the bullets are scoring it? The SAK is so light I'd be surprised if the barrel is touching the stock when fitted but it's possible when harmonics are factored in. You need to free float the barrel now if you have already tried another mod to start to eliminate other factors. Let us know how you get on Si Link to comment Share on other sites More sharing options...
fizzbangwhallop Posted July 15, 2012 Report Share Posted July 15, 2012 try one of the old style parker hale mods works a treat on my .17 ...........and you can wrap your wet n dry around it to open out the barrel channel with it too....... Plenty of air around my barrel now and I had the action bedded by Norman Clark! I did have to do the channel again the following summer as the stock had moved over the winter. I did seal the bare wood with a wipe of varnish on a cloth the first time but it still moved. It could be possible that your front sling stud is touching the barrel with the bit of extra weight of the mod on it, although I thought the SAK's didn't weight that much. Got an Ase Utra on mine and a Sirocco SM2(?) on the Finnfire 22. If I remember correctly some people grind the front trigger guard screw down as well as it can bear on the underside of the acton and affect accuracy although that's unlikely to be the problem here. Trying a different moderator first is the way to go as others have said though. atb Fizz Link to comment Share on other sites More sharing options...
Bad Wolf Posted July 17, 2012 Report Share Posted July 17, 2012 If the problem is occurring with two mods and the gun prints OK without, then I'd guess that the muzzle thread is not concentric to the bore. Link to comment Share on other sites More sharing options...
CZ Varminter Posted July 18, 2012 Report Share Posted July 18, 2012 Just sell it and buy yourself a proper calibre! .22 will not fail you. Link to comment Share on other sites More sharing options...
onehole Posted August 11, 2012 Report Share Posted August 11, 2012 Picked up on this topic mainly as I,m using a Sak mod on my anschutz 17hmr and to be honest have never been really pleased with the way my rifle shoots.have put it down to ammo,bad batch or expecting too much especially if there is some wind around,However i,m going to try some serious grouping with and without the mod,,,cant think why I have not tried this yet,,,,not like me at all but I have noticed sometime ago when using a particular brand of mod on a 6.5/55 it seemed to suck or retain a lot of debris back into the bore and accuracy was poor compared to shooting it with another make.The Sak could be sucking back or keeping debris a little more than the small 17 bore likes.The bore is definately dirtier when using the mod than without so may just be part of the problem?Will come back on here when I,ve given it a fair test.Onehole. Link to comment Share on other sites More sharing options...
onehole Posted August 14, 2012 Report Share Posted August 14, 2012 Picked up on this topic mainly as I,m using a Sak mod on my anschutz 17hmr and to be honest have never been really pleased with the way my rifle shoots.have put it down to ammo,bad batch or expecting too much especially if there is some wind around,However i,m going to try some serious grouping with and without the mod,,,cant think why I have not tried this yet,,,,not like me at all but I have noticed sometime ago when using a particular brand of mod on a 6.5/55 it seemed to suck or retain a lot of debris back into the bore and accuracy was poor compared to shooting it with another make.The Sak could be sucking back or keeping debris a little more than the small 17 bore likes.The bore is definately dirtier when using the mod than without so may just be part of the problem?Will come back on here when I,ve given it a fair test.Onehole. Well I,ve done some testing today using three different batches of the same Winchester brand ammo and all three batches went to the same point of aim at 100m and grouped into an inch appx with the SAK mod fitted.I am quite pleased with this as there was still some wind around and those groups would certainly have tightend up in calm conditions.However it was a different story with the moderator off with noticably worse groups although none bigger than 1.5 inches and impact/group shift between the three lots,,,,,verdict ,,,,the mod stays on and one inch grouping is probably all we can expect from the mass produced factory ammo ,,,,just accept it.regds Onehole Link to comment Share on other sites More sharing options...
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