I Need Some Suggestions re: My AK

[Treetop]

I've been shooting my MAK 90 with the Lee 155 gr. GC bullet (.313" dia.) using WQWW with 14 gr. of 2400 powder. The bore slugged at .312".

Yesterday, while cleaning the rifle, I noticed some leading at the muzzle. Upon further investigation, I found the leading was unique in two respects:

1) The leading was only present from the gas port forward and,

2) The leading seemed to be most concentrated around the rifling that the gas port was drilled into.

This rifle has a chromed bore and chamber, so I really don't know how to resolve this problem.
Shoot some low velocity "lapping loads" through it to smooth out the sharp edge of the gas port, despite the chromed bore?

Don't worry about it and just shoot a few "J words" through it at the end of each training session?

Something else...? Thanks, Tt.

[mooman76]

I would guess you have a slight rough spot around the gas port. Is your's a fairly new gun? If so it may wear on it's own or you could run a few hundred jacketed bullets through it. If the lead comes out easy, I wouldn't worry about it. Someone else might have a better idea but that's what I'm a thinkin.

[Treetop]

Is yours a fairly new gun?

I bought it new back in the 90s, but I probably haven't fired 150 rounds of jacketed bullets through it. Mostly Lee cast boolits. That's a good idea, Moonman76. I may buy a bunch of that cheap Yugo ammo on the market now, that's slightly corrosive. I saw it advertised online recently for < 5 cents a round. Tt.

[mooman76]

By the way, mine is a Mak90 also but I haven't fired cast through it yet.

[onondaga]

You may need a larger diameter boolit to stop the leading. You slugged at .312 and your boolits are at .313, The .001 may not be tight enough in your bore to stop gas jetting .

The problem may also be the way you prepare your brass and seat your boolits . Use a bullet puller and measure the diameter of a pulled boolit in the area seated below the case mouth rim. If seating has swaged your bullets below .313, they are too small.

I had a similar problem and solved it by using a Lee Collet Neck sizing die with a mandrel from a .303 Brit die. The larger inside neck diameter then did not swage down the bullets when seating them. But my rifle is not a semi auto. You could use a Lyman M die for 31 caliber after sizing and likely solve the problem for a semi auto. M die, 31 cal is only available for long cartridges like the .303 Brit. But I bet you can shorten it.

I bet this seems like a pain in the butt. Sometimes a change in alloy and casting technique can bring up boolit diameter another .001"

I honed out my boolit mold and my sizing die and customized a collet die to get my x39 to shoot accurately. It wasn't easy but I get .885" groups at 50 yards now instead of 2 inches at 50 yards with undersized boolits.

Gary

[Harter66]

I've a Yugo sks that does exactly the same thing clean shiny bore right up to the gasport,then gravel road w/a lube star. Mines not chrome so the bare laps helped some. The most help has come from paper patching its work but is worth it. I'm still working the load out but what a treat to shoot 60-70 rd w/o any lead in the piston,port,or BBL.

FIW I shot boolits from 314-323 ,the 323s fit the throat, all w/lead beyond the port.I read somewhere that if a land is drilled for the port that it is rare to have it work out completely,I can't remember where.

[Treetop]

The most help has come from paper patching its work but is worth it. I'm still working the load out but what a treat to shoot 60-70 rd w/o any lead in the piston,port,or BBL.

Harter66, I actually considered paper patching the Lee 155 gr. boolits for the MAK- 90, but I wasn't sure that it would cure the leading problems caused by the gas port.

I already paper patch for my .30 calibers, and yes it would be more work for the fast firing MAK-90! Tt.

[truckmsl]

Shooting more jacketed should help with the muzzle leading if it's due to a gas port burr. I've got a MAK and shoot cast through it all the time with no leading at the muzzle end, but have also pushed a lot of jacketed through it in the past. I use a .314 boolit for mine. My gas port is drilled through a land.

[JIMinPHX]

Please pardon a stupid question...

Are you using gas checks?