SKS after the front sight and bayonet lug are removed and barrel shortened...

[scottnc]

I am considering removing both the front sight and bayonet lug then shortening the barrel back to the step for the lug on a CCP made SKS. For anyone who has shortened an SKS barrel, what if any effect did the shorter barrel have on the gas system operation and group size?

Before someone asks, the reason for shortening the barrel is doing so gets rid of several of the pressed pin bore bulges and hopefully stiffens the barrel. The rifle is scoped, the mount - modified to finally be solid - has proved no need remains for a front sight, can't see it anyway. Also, this particular rifle wouldn't stay on the two foot square piece of cardboard for four shots at 100 yards. After lapping the barrel, bedding the receiver and the barrel under the very tip of the stock for-end, adding a rear receiver hold down screw and playing with handloads, it still has a third or fourth shot vertical flier. Usually high.

[cwtebay]

I did that to one in the 90's because of the dimple created by "exuberant" bayonet use. I don't recall any part of the process being fun. I did finally employ a LGS to get the gas system back to functional. It never did reliably cycle again, I think of it as similar to an over gassed AK in function. I relayed that tale not to be discouraging, just my experience.
I'll bet someone on here knows far more than I about the proper procedure.

Sent from my Pixel 5 using Tapatalk

[Der Gebirgsjager]

I removed the front sight and bayonet, but reinstalled the front sight. I filled the pin holes and polished them to match the barrel's contour. Bulges I noticed were on the surface of the barrel from the pins being inserted, but not inside the bore, and they were removed. Because I did not shorten the barrel I had no gas problems. They did make a shorter version called the "paratrooper model", and one could examine one to see what the difference is.

DG

[Uncle Grinch]

I never like the looks of the SKS with the internal bayonet. Too much crap hanging off the barrel for my likes. Now yours looks good and I would definitely consider picking one up.

[LAGS]

I did the same on a SKS that I had for hunting.
There was no need for a bayonet or cleaning rod while hunting.
I too don't like a lot of things hanging on my rifles.
I can't stand seeing AR's with all kinds of rails with everything under the sun hanging on them like red dots , flashlights , scopes etc.
But the rails might be good if they designed a coffee maker to hang off the rail.

[scottnc]

I removed the front sight and bayonet, but reinstalled the front sight. I filled the pin holes and polished them to match the barrel's contour. Bulges I noticed were on the surface of the barrel from the pins being inserted, but not inside the bore, and they were removed. Because I did not shorten the barrel I had no gas problems. They did make a shorter version called the "paratrooper model", and one could examine one to see what the difference is.

DG

The barrel bulges from the front sight and bayonet lug pins were prominent enough stop a snug patch, the front sight especially. I re-crowned the barrel twice trying to fix it before figuring out the patch was stopping just short of reaching the barrel crown.

A quick measurement suggested cutting the barrel at the bayonet lug should result in a barrel length maybe a little longer than 17", so roughly 5/8" longer than the paratrooper version.

I could find no mention about the paratrooper gas system being any different than the common threaded barrel Norinco. The gas block is currently restricted to .070" a size I find works well with lead boolit handloads using 4198, RL-7 and 3031 in Starline brass. Several times fired cases still look pristine.


I have a tool from Brownell's to re-crown the barrel and a lathe turned lap. Bought the re-crown tool for a Shilen re-barreled Remmy 721 in Ackley 30-06 nearly thirty years ago . . . gosh, am I that old?

[Der Gebirgsjager]

If you're going to cut the barrel off just behind the front sight I wouldn't anticipate any gas flow problems. Farther back, there will be less pressure and you may have trouble.

I've never stripped and examined a paratrooper model myself, so maybe there is no difference, in which case there would be no reason that you couldn't shorten the barrel to that length, proven to work. I guess, unlike the finicky AR-15, they don't require different gas ports and blocks to function with different barrel lengths. Oh...there's another possibility, the paratrooper model may have a different size gas port, probably would be a bit larger to compensate for less pressure. I don't know.

Assuming that you have a screw-in barrel they aren't that hard to re-barrel, and the pressed in and pinned barrel isn't too much of a problem either. Replacement barrels are available, should your experiment go wrong.

DG

[Gtek]

I have one that was counter bored at some point in past and have debated doing the same one day. I have a lot of rather expensive carbide muzzle cutters and I will refrain from using any of them on a chrome lined bore. It will be hack, file and lap and hope for the best, doubt it could be much worse than it is now. Shortening the barrel reduces dwell time in a way over gassed system IMHO and it runs fine with two inches of bore gone. I have a shooting bud who has owned one of the since imported "Paratrooper" models, it has went bang and run every time it was out.

[scottnc]

I have one that was counter bored at some point in past and have debated doing the same one day. I have a lot of rather expensive carbide muzzle cutters and I will refrain from using any of them on a chrome lined bore. It will be hack, file and lap and hope for the best, doubt it could be much worse than it is now. Shortening the barrel reduces dwell time in a way over gassed system IMHO and it runs fine with two inches of bore gone. I have a shooting bud who has owned one of the since imported "Paratrooper" models, it has went bang and run every time it was out.

You are the second to comment on the chrome lined bore. This is the only firearm I've owned with one. Lapping this SKS's bore with a linotype plug has had no ill effect I can see, am I to assume the chrome is apt to chip rather than cut clean?

[Gtek]

The chrome may/can damage the carbide cutting device.

[scottnc]

The chrome may/can damage the carbide cutting device.

Thought about that after posting.

[scottnc]

Never succeeded in getting the front sight/bayonet lug off, fortunately there was a gap behind the lug that was a perfect fit for a hack saw blade. The chrome did not have an adverse effect on my barrel crown tool. It did however do a number on the radius lap until going to the finest grade of lapping compound. Did a good job using a slow speed with steady, light pressure (weight of the drill motor).

[Milsurp Junkie]

It would be easier to counter bore it past those areas. Try it, if it doesn't work you can cut off and recrown it.

[scottnc]

It would be easier to counter bore it past those areas. Try it, if it doesn't work you can cut off and recrown it.

It is counter bored after a fashion. The crowning tool I used cuts a concave angle of maybe 20° included offering some protection to the rifling. I then used a radiused lap to dress only a very narrow band of the end of the rifling. The initial lapping compound selected proved inappropriate, the chrome rifling chewed up the lap! After dressing the lap and switching to a finer compound all was well. I'm quite happy with the results. After hitting it with a little cold blue the end product looks better than factory. Now I need the weather to cooperate.

[Milsurp Junkie]

Try it. If it doesnt work counterbore it past the constriction and try it again. It would be easier to try that, see if it works, and if it doesn't chop the bore and move the sight...