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S308 recoil spring?


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Hi guys, had a quick question about the s308 recoil spring. Is it the same as other saiga rifle recoil springs? I ask because my s308 has developed a nasty problem where my first shot will be on where i zeroed my scope, and all auto loaded rounds will impact 3 inches left and 2.5 inches high(eta: @100yds), even letting the barrel cool down between shots. Since the primary function of this rifle is hunting, I'd like to minimize the point of impact shift between hand racked and auto loaded rounds. I did a little digging and read that swapping recoil springs might help, but i havent been able to locate a s308 specific recoil spring. Thanks in advance for the help.

Edited by LuPiN8oR
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Its a vortex viper pst 2.5-10 mounted on a midwest industries side rail mount. Its adjusted pretty damn tight too. All rings are blue loctited as well. The POI shift is repeatable to an insane degree, i shot at least 5 5 shot groups and the first racked round left a 1.5moa hole right where its zeroed, and all subsequent auto loaded rounds left a cluster 3in left and 2.5in higher. If i hand load each round I'll get a nice tight group. In my research i read that the recoil spring can come into play because of the force it exerts in seating the auto loaded rounds. I just hope itll take care of the problem bc i dont wanna have to use a semi auto as a single shot gun you know! Im aware of the 'first round flier' issue but im wanting to try to shrink that deviation as much as possible. Thanks again for the help.

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When loading the first round, are you letting the spring use full force to lock the action? Try pulling the bolt back forcefully and letting your fingers slip off when it gets to the end of rear travel. DO NOT BE NICE!

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  • 2 weeks later...

So, i received the new recoil spring i ordered from CSS and upon installation noticed the new spring was about 3/4 of an inch shorter than the o.e.m saiga spring. Hopefully it will be a non issue. Guess we will see. Anything i should be on the lookout for if it cycles properly, like my rear trunion, etc? Thanks again for the input.

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Well, the new spring did it. It did away with the first round flier and now all shots including the hand racked one fall within a 2in spread at 100yds if i dont screw up. Tightest group was 1.25in at 100yds using win super x 150gr powerpoint.

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  • 2 weeks later...

I shot my rifle for groups at 100 yards on Sunday with the Wolff extra power recoil spring installed.  While it did not fix the low first shot from a cold bore, I didn't really expect it to.  The rifle just seems much happier in general, especially when fired through the can (AAC SDN-6), to the point that I think that's going to be the way to shoot it from now on.  When I shot it through the can before, I was not happy with the performance at all, or the added violence of the action cycling due to the increased gas pressure.  With the heavier spring it is much smoother now.

 

The best group of the day was 5 shots into 1-3/16", with two others measuring under 2" each, and another that would have been under 2" except for the low first round.  Brass chucking is still kind of random, although whereas before, it seemed to throw more of them way forward, it only did that with a couple rounds, with most of them falling much closer and more to the right.

 

If I can find the cause of, and alleviate the low first round issue, I think I will really have something.

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Just try a new standard ak spring, the extra power one may have something to do with it. I bought my s308 used so it may have had an extra power spring installed without my knowing. I do know however, that it was longer than the one i installed to fix the flier issue. My first round might still be impacting lower but it brought my group size down to a managable level for hunting. Good luck!

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The improvement in how the rifle cycles was good enough that I have no intention of changing the spring again, and I am pretty sure that my issue is due to heat.  I figured it was to begin with, but had nothing to lose by trying the stronger spring, and I am glad I did.  I fired one group that was all single-loaded, and it didn't make any difference at all.  I checked the gas tube once before and it didn't seem to be too tight, but I will check it out again.  It's also possible that it's related to fit of the handguard.  There isn't really another handguard on the market that I like, so I haven't wanted to change that out.

 

It's obvious at this point that Ultimak will never come out with their gas tube/rail for the S-308, which I had hoped I could use to eliminate the gas tube as a possibility.

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If I could just get it to do this more consistently...  Yeah, that'd be good.

 

308t-5.jpg

 

Fiddled with the rifle some more tonight.  I loosened up the fit of the gas tube a bit so it can be wiggled a little now, and I removed the sheet metal cover piece that was spot welded to it, because I didn't care for the way it looked.  Rattle canned the gas tube flat black for now, because once I either get the rifle to do what I want it to, or I give up, I am going to give the whole thing a real refinishing.

Edited by Netpackrat
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So, I removed the sheet metal cover that was spot welded to the gas tube, and then I relieved it anywhere it was tight where it interfaces with the rear sight block.  So now it has a slight amount of wiggle to the whole unit.  Test fired it at the range today, and could detect no POI shift going from a cold bore to hot.  So, I am going to tentatively declare victory on that.  Then my can loosened up on its mount (fuck AAC!) and turned my accuracy to shit.  I should have listened to everybody who was trying to steer me towards the SilencerCo Saker.  The main reason I went with AAC, is they make a flash hider in 9/16-24RH, which is what the Saiga .308 is threaded.  Do not want a muzzle brake on a 16" .308, and did not want to have to change MAAD mounts on the SiCo can to move my "quick mount" can between rifles, since that would kind of defeat the purpose of a quick mount can in the first place.  But AAC's 51T mounting system sucks.  And once you have a can, it is pretty much yours for life.  booo.gif

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I'm waiting on a silencerco omega to get out of NFA jail...just out of curiosity, did you thread the barrel of your s308 yourself? If so, why didnt you thread it 5/8-24? Im just curious because i am wanting to thread my s308 and really hoping 5/8 will work for cross compatibility.

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No, I had a gunsmith thread the barrel properly in a lathe.  9/16" was the largest thread diameter that was possible for full engagement and a good shoulder.  The 90 degree shoulder at the end of the threads is an important factor in getting proper suppressor alignment, and you are not going to achieve that with the redneck method using a die and alignment tool.  Seating the can/mount against the front of the FSB is unlikely to be accurate enough.  The die/TAT method is good enough if all you want is to install a muzzle brake or flash hider, but if there is ANY possibility you may want a can at some point, pony up the bucks to have it done right, because you only get one shot at it (with a 16" rifle, at least).  Considering the cost of a can, and what can go wrong, spending the money on good threading is a no-brainer.

 

Conventional wisdom is that you have to have the barrel removed to accomplish this...  But it isn't necessarily so.  Although I am equipped to press barrels, my gunsmith was able to chuck the rear of the receiver in the 4 jaw chuck of his lathe, and with the muzzle in a center, indicate the barrel into alignment (this takes a fairly large lathe).  A buddy had his VEPR done at the same time, and due to the slant back receiver, he wasn't able to chuck it up, and we had to pull the barrel on that one.  And after having a barrel turned between centers (which again, is the RIGHT way to do it), the barrel should also be re-crowned, which is usually beneficial for a Saiga rifle in any case.

 

The end result is, while I am having trouble with my can and it's mounts, I don't have any misalignment issues on either of the rifles I had him do.  He's currently got the barrel for the AK SBR I am building and I am looking forward to getting it back.  Not sure yet what thread size it will end up with.  Probably 1/2-28, but he thought 9/16-24 might also be possible just based on a quick caliper check of the OD.

 

One other piece of advice I can offer, is always check alignment.  An AR upper I bought is currently back at the manufacturer because of misaligned muzzle threads, which I found prior to shooting it.  The guy I talked to on the phone was appreciative that I checked...  They don't want to be blamed for a wrecked can and possible shooter injury, any more than I want to be involved with those things.  Hopefully I will get it back soon, fixed.

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  • 1 month later...

Well, i figured i should post an update and let everyone know that the recoil spring swap was a short lived fix. She's now back to a 3inch deviation between the 1st racked round and the auto loaded ones. It worked well at first but i am now at a total loss as to how i should go about remedying this or if i should even bother trying. The only upside is that if i zero the hand racked round dead on elevation and one inch left, all subsequent rounds land 1in right and 2.5inches high. So in theory it can still be used for hunting if you use a hold over if you're shooting out to 200yds on the 1st round and pretty much point blank for all others. Ive tried superx 150gr and federal 150gr sp with the same results. I might try a different weight and kind of bullet but outside of that i don't know what else can be done.

 

Eta: where exactly did you loosen your gas tube fitment? I may try that if you think it was a factor.

Edited by LuPiN8oR
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  • 3 weeks later...

I finally got around to digging my rifle out, and when I looked at it, remembered that I can't remove the gas tube without first taking out the forward pin of the TWS scope mount, because the 3x9 scope overhangs it in the front.  I didn't feel like doing that or removing the forend which would have given at least a partial view of what I did.  Maybe next time I have it apart, but honestly I am not sure that a picture would be totally useful anyways.

 

Mainly what I did, was to remove the outer sheet metal cover that is spot welded onto the gas tube, and then relieved the tube slightly at the front so that it wasn't pressing on the gas block at all, and at the rear so the bottom didn't press against the barrel, and at the top so that the gas tube retaining lever isn't such a bitch to move (it used to require pliers).  Basically the idea is to make the entire gas tube assembly slightly loose, so it's not pressing anywhere.  Then, as the barrel heats up, since the tube wasn't pushing on it to begin with, it can't change as the barrel expands slightly in length due to heat.  I didn't remove so much metal as to make the gas tube rattly, just loose enough that it can be wiggled a little.

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  • 3 weeks later...

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