THE VEPR FORUM

Atterete Dominatum
It is currently Thu Apr 26, 2018 7:48 am

All times are UTC




Post new topic Reply to topic  [ 5 posts ] 
Author Message
 Post subject: AK Adjustable Gas Piston
PostPosted: Sat Mar 17, 2018 3:21 am 
Offline

Joined: Thu Aug 08, 2013 9:44 pm
Posts: 20
Anyone try the KNS Precision 'Adjustable Gas Piston' yet? I'm wondering how much FHS (Flaming Hot Sh!t) it's going to be dumping in the belly of my beast?

I just got one for my 308 and I am going to be messing with it next week.

They say if your rifle is throwing brass 15' you are over gassed and just beating up yourself and your rifle. Me? I figure if it's a Kalashnikov it's probably over gassed. Mine kicks like hell even with a HD recoil spring and a Fab Defense 'Recoil Reducing' Collapsible Butt-stock; and that is weighing in at a plump 13.8 lbs with a full 10 round mag, bi-pod, mono-pod, padded leather hunting sling and a 4x16x40 scope.

It's not as bad as my 7.5 lb (w/Scope and Sling) loaded Winchester 88, but still it is not what I would call pleasant at all; and more important, the time to get it back on target accurately is excessive. Truthfully it was better before (quite a bit better) when it wore just a $20.00 'Limb Saver' on it. I have one on the 88, and with it on that thing shoots like a different rifle.

https://www.knsprecisioninc.com/product/ak-adjustable-gas-piston/ ...I hope it's worth the $149.00.

I really want to be able to tune reloads for it, but the AK Ding has been hellatious with everything I have run through it; so I mostly shoot surplus and Tula until I can manage to get the Ding (Giant Case Crease) issue under control.

After I have the 'BCG Slam' thing tamed, I am thinking that I might also shorten the barrel, have it crowned and threaded for a Brake/Compensater to help get it back on target faster.


Top
 Profile  
 
PostPosted: Sat Mar 17, 2018 4:53 am 
Offline

Joined: Mon Jan 02, 2017 9:06 am
Posts: 55
Maol wrote:
Anyone try the KNS Precision 'Adjustable Gas Piston' yet? I'm wondering how much FHS (Flaming Hot Sh!t) it's going to be dumping in the belly of my beast?

They say if your rifle is throwing brass 15' you are over gassed and just beating up yourself and your rifle. Me? I figure if it's a Kalashnikov it's probably over gassed. Mine kicks like hell even with a HD recoil spring and a Fab Defense 'Recoil Reducing' Collapsible Butt-stock; and that is weighing in at a plump 13.8 lbs with a full 10 round mag, bi-pod, mono-pod, padded leather hunting sling and a 4x16x40 scope.


I'm in the group that says its not going to make much of a difference. 15' does sound a little far. I dunno, mine shoots like a baby, but its not stock either. Decided to tear my scope off, too heavy. I still get case dings occasionally if I remember right, but theyre light. Would need to go look, been awhile since I really payed attention, lol.

When I had the barrel shortened on mine, it wouldn't cycle afterwards. Ended up enlarging the port hole ever so slightly. It runs nice, eats anything. Fine tuning with one of those gas pistons could probably achieve something really light. Ive just been too happy with the results to fork over the cash.


Top
 Profile  
 
PostPosted: Sun Mar 25, 2018 2:51 am 
Offline

Joined: Thu Aug 08, 2013 9:44 pm
Posts: 20
Six wrote:
I'm in the group that says its not going to make much of a difference. 15' does sound a little far. I dunno, mine shoots like a baby, but its not stock either. Decided to tear my scope off, too heavy. I still get case dings occasionally if I remember right, but theyre light. Would need to go look, been awhile since I really payed attention, lol.

When I had the barrel shortened on mine, it wouldn't cycle afterwards. Ended up enlarging the port hole ever so slightly. It runs nice, eats anything. Fine tuning with one of those gas pistons could probably achieve something really light. Ive just been too happy with the results to fork over the cash.


Six, I probably should have had the barrel shortened first given your experience, but I already the piston so...

I haven't gotten around to the accuracy portion of the testing yet, but I did get it installed and ran 20 rounds of 150 gr Tula 308 Win through it. I used 2 different 10 round Molot Mags and realized I have some work to do yet on the magazines. I am going to search the site for words of wisdom about those. Both have always been a bit of a PIA to rack with, but the bolt always stripped one off and we never had a FTE or FTL.

With the first magazine, after a FTE and a FTL where the bolt came to a dragging stop on the magazine, I closed the piston a little more and viola, I had found the sweet spot with piston and the seventh round landed 2 ft away (on the bench) it loaded the eighth etc, and all four empty cases landed close to about the same spot. The second magazine was where I had more issues and got some insight. It still had issues, one FTE so I closed the piston some more and it still had 3 FTLs (I closed the piston 2-3 notches after each) I stopped adjusting the piston after I realized I could move the magazine and the hung bolt would complete it's cycle and close. So I finished the second off while playing with magazine and decided not waste anymore ammo.

So from this range session I learned that the piston works, and my Molot magazines' interface with BCG is a real drag. Oh yeah and the recoil is still there, but the rifle isn't jumping around like a rabid kangaroo, and my time to back on target was at least halved. The steel cases had no dings but many had lines from the BCG running across them. By the way I ran the rifle today with out a scope or my sling, just used the peep and stock front sights so it was close to 2 lbs lighter than usual.

I hope I will be able do some accuracy stuff tomorrow afternoon and be able to work with some different ammo too.


Top
 Profile  
 
PostPosted: Thu Apr 05, 2018 2:48 am 
Offline

Joined: Thu Aug 08, 2013 9:44 pm
Posts: 20
Six wrote:
I'm in the group that says its not going to make much of a difference. 15' does sound a little far. I dunno, mine shoots like a baby, but its not stock either. Decided to tear my scope off, too heavy. I still get case dings occasionally if I remember right, but theyre light. Would need to go look, been awhile since I really payed attention, lol.

When I had the barrel shortened on mine, it wouldn't cycle afterwards. Ended up enlarging the port hole ever so slightly. It runs nice, eats anything. Fine tuning with one of those gas pistons could probably achieve something really light. Ive just been too happy with the results to fork over the cash.



Six, out of curiosity what was the original barrel length and what did you cut it down to? Was it noticeably more accurate?

BTW I still haven't gotten around to the accuracy portion of the testing yet, but I did get to shoot it with brass cased 308 - PMC and 7.62 NATO - ZQ1. 2 mags of each, using the same ones from the tests with the steel-cased Tula 308 Win. The problem is not just the mags, it is the Tula. I did a search about the Molot mags, and it appears to be pretty common with steel-cased ammo. As I said, both have always been a bit of a PIA to rack because of the BCG drag; but with the steel case the friction is much worse with the BCG even gouging the coating. It never mattered before, I guess from being “Natively” over-gassed, the bolt always stripped one off.

Using the setting on the KNS piston where I had left it after the bolt kept coming to a dragging stop on that 2nd magazine when I was testing with the Tula worked with the 308 win for both mags with out a hitch. I opened the piston 2 clicks and it still worked as I finished both mags out. Not so much with 7.62 NATO, although one seemed to be better than the other. I closed the piston back up 2 notches and pulled the mag back towards my shoulder and emptied it. No more stoppages for either one magazine.

I am just going to have to bite the bullet, and get me some Csspecs magazines soon I guess.

So, from this range session I learned that the piston works nicely, and confirmed that one of my Molot magazines has a bad fit. With the rifle weighing in at 11 lbs. and the KNS piston adjusted for the 7.62, the felt recoil was improved and the time to reacquire the target was much faster than with the stock piston even with rifle weighing in at 14 lbs loaded.

I hope I will be able get enough time and good weather to get the accuracy tests done soon. Winter just doesn’t seem to want to die, and for some reason I keep having to work whenever it is half way nice…


Top
 Profile  
 
PostPosted: Sat Apr 07, 2018 9:53 am 
Offline

Joined: Mon Jan 02, 2017 9:06 am
Posts: 55
The build is here: viewtopic.php?f=12&t=6625

Think I started with a 20, and ended up with a little over 16, with the brake permanently attached. Accuracy is probably worse. I got tired of the scope, before having a chance to get setup on a rest somewhere, and try some decent ranges. Plus don't have before results to compare it with. Last time I shot mine, I came across a pump platform over a frozen river, and lit up a plastic 55 gallon drum that was out on the ice. Spray and giggle. The irons are really pretty decent though. I just think of it as more of something I would grab for close/midrange use.

I'm a fan of Prvi brass. Its fairly cheap, yet still produced with decent materials. Its just not worth it to mess with steel for me, but I suppose other people who go through thousands of rounds a month might think otherwise. Never tried any of the stock magazines. They're still bagged up. My rifle came with some converted M1A/M14 Mag's. Csspecs is supposed to make some nice stuff, but since I have the recipe on my current mags, they can just be duplicated.

Good to hear the piston is working out for you. Yeah, sounds like your eating some recoil with the extra gas to make your magazines function. I tend to put a light coating of literally bearing grease on my rails, and bolt. You probably have your own methods of such things anyhow already. I'm guessing the 308 Win is probably a bit hotter than the 7.62.

Since you're already inside your rifle quite a bit working with the piston, you might consider grabbing some plumbers putty, or something of that nature, and basically pressing a thin layer onto your rear trunnion, where your carrier may come into contact. (Actually duct tape would probably work too.) You should be able to tune to no contact in that area. If you end up with smashed putty, you're still overgassed. Also check the action by progressively releasing the carrier at lower heights, chambering a round. It should go through nice and smooth, even when not exactly all the way back. Sorry if I am babbling things you already know.

This has really been a great light shooting rifle for me, though I'm probably not very recoil sensitive either. My lady said it shot nice and smooth for her also, but she handled my DE .50, and .357 S&W Jframes decently, shooting them on more than one occasion. So I really don't know.

Don't even get me started on winter. I've had a few choice words with mother nature lately. Something like 68 yesterday, now looking outside to snow on the ground. Ridiculous.

(Just a disclaimer, its early AM, and I may be babbling some nonsense, so take anything I say with a grain of salt.)


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group