Project RatRod: SKS shorty

On a rifle with a conventional brake, the ports are at 0, 90 and 180[SUP]o[/SUP]. The gases from the muzzle pass through the ports. The upper port at 90[SUP]o[/SUP] helps prevent muzzle rise. The ports at 0 and 180[SUP]o[/SUP] reduce recoil. We agree on this.

What reduces the "tendency is for the rifle to jump upward and to the side of your strong shoulder during recoil. Shooting right handed, the rifle jumps up and somewhat to the right"? This statement implies that conventional brakes should be designed for left and right handed shooters.

The recoil of a firearm is directly in line with the bore (Newton's third law). Because the center line of the bore is normally above the point of contact of the stock with the shooters shoulder there is muzzle rise. This is why the M16 stock is directly in line with the bore. The design virtually eliminated muzzle rise and reduced target reacquisition time.

The SKS bolt travels in a straight line, from the breech to the rear of the receiver and back again. It locks by dropping into the bolt carrier. The AK bolt is similar but with one major difference; it locks to the barrel by rotating. It is because of this that the AK slanted brake is installed at a slight angle to the bore. The angle allows the muzzle blast to oppose the rotation of the locking bolt and helps keep the rifle vertical. The open top of the brake prevents muzzle rise.

I have a slant brake on my SKS and truly enjoy it. Muzzle rise is substantially reduced and the typical increase of heard blast associated with using a brake is almost nonexistent. My brake is, however, aligned at 90[SUP]o[/SUP] to the muzzle. See http://www.canadiangunnutz.com/forum/showthread.php?663216-SKS-Folding-Stock-Project

I offer this only for your consideration. If the brake installed as you have it works for you, then by all means do not change it.

Have a great weekend, well, what's left of it.

ct

supernova said:
Its simply a function of design. The Slant comp directs gas in one direction only, and thus produces a force in the opposite direction. Remember, it is as simple as muzzle devices get. Newer designs direct gases in multiple directions to accomplish different goals. Two opposing ports 180 deg. from each other will cancel each other out as far as applying any force but recoil is reduced as that gas is not creating the thrusting force that makes up a lot of recoil. Angled ports, like on top of the Czech VZ-58 brake are for compensation to keep the muzzle down and help prevent side movement while the side ports reduce recoil. The slant comp simply applies one force in one direction to directly counter what happens during recoil. It pushes in the opposite direction the muzzle is trying to go to help keep you on target.
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Charles please explain why my SKS' jump up and to the right without a muzzle device and only slightly up and not to the right with the slant comp. Also explain why the same is true for my CZ858. Neither have a rotating bolt. Both work best with the slant comps angled to the right. It has nothing to do with the rotating bolt.
 
The rotating bolt is a moot point. Are you seriously saying that a little moving part in the receiver torques the whole gun uncontrollably while firing?? Lots of auto's and semi's with rotating bolts out there, why no slant brake on them?
 
If your rifle is moving up and to the right when fired, it may be one of several issues.

The movement up is likely muzzle jump, and the brake will help with that.

The movement right may be caused by canting or an incorrect sight picture. Try shooting off a steady rest and see if that reduces the movement.

ct
 
Charles I know how to shoot a rifle. The flip to the side is caused by recoil pushing on my strong shoulder which has give (basic body mechanics) this give allows the rifle to walk to the side some during recoil and the slant comp on an angle corrects it. That's how Mikhail designed it to work for FA fire with the AK and it works equally well for faster follow up shots with a semi. That's why I chose it, previous experience tells me its the perfect comp for this build and range time proved that to me as it did with my CZ. I don't know how else to explain this to you. Its a simple one direction compensator angled ideally to counter act muzzle flip and give me the quickest follow up. It does exactly that how its installed.

CharlesT said:
If your rifle is moving up and to the right when fired, it may be one of several issues.

The movement up is likely muzzle jump, and the brake will help with that.

The movement right may be caused by canting or an incorrect sight picture. Try shooting off a steady rest and see if that reduces the movement.

ct
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Do you also notice this effect when shooting other rifles?

The reason I ask, and I guess the reason for this whole discussion, is that I have never experienced it.

ct

supernova said:
Charles I know how to shoot a rifle. The flip to the side is caused by recoil pushing on my strong shoulder which has give (basic body mechanics) this give allows the rifle to walk to the side some during recoil and the slant comp on an angle corrects it. That's how Mikhail designed it to work for FA fire with the AK and it works equally well for faster follow up shots with a semi. That's why I chose it, previous experience tells me its the perfect comp for this build and range time proved that to me as it did with my CZ. I don't know how else to explain this to you. Its a simple one direction compensator angled ideally to counter act muzzle flip and give me the quickest follow up. It does exactly that how its installed.
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That depends entirely on the rifle, the amount of recoil and the muzzle device used. With the SKS, CZ, M1 etc with no muzzle device they all flip up and slightly to the right. The Dlask AKM on my CZ greatly reduced it and the surplus AK comp on the SKS does too. The NEA crusader brake on the CZ eliminated all side movement but left a little muzzle flip. It also greatly reduced felt recoil which is what causes the flip to the side. Low recoil rifles like .22s just don't have enough recoil energy to cause any side movement for me. My XCR with a YHM phantom comp had zero muzzle flip but a little side flip. Ganderite had the same issue with an AR and solved it by canting his muzzle device.

CharlesT said:
Do you also notice this effect when shooting other rifles?

The reason I ask, and I guess the reason for this whole discussion, is that I have never experienced it.

ct
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CharlesT said:
Do you also notice this effect when shooting other rifles?

The reason I ask, and I guess the reason for this whole discussion, is that I have never experienced it.

ct
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So you've never shot an AK full auto, eh? Thanks for lending your experience to the conversation on the topic of brakes for full auto AK's.
 
I have fired many designs and calibers of rifles and never experienced this. From your description of the issue, I would imagine that this effect would occur on any style of rifle. I do notice however that all the rifles you mention are semi auto. Have you noticed this effect on a bolt action?

ct

supernova said:
That depends entirely on the rifle, the amount of recoil and the muzzle device used. With the SKS, CZ, M1 etc with no muzzle device they all flip up and slightly to the right. The Dlask AKM on my CZ greatly reduced it and the surplus AK comp on the SKS does too. The NEA crusader brake on the CZ eliminated all side movement but left a little muzzle flip. It also greatly reduced felt recoil which is what causes the flip to the side. Low recoil rifles like .22s just don't have enough recoil energy to cause any side movement for me. My XCR with a YHM phantom comp had zero muzzle flip but a little side flip. Ganderite had the same issue with an AR and solved it by canting his muzzle device.
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Ive never paid attention as a fast follow up is not going to happen like it will with a semi. Cycling the bolt moves the muzzle around far more than the side flip I get with most semi's so even if it did happen it doesn't slow me down that tiny bit if I want to double tap or even just rapid fire. The slant comps reduce time between aimed shots quite noticeably for me while being very compact, easy on the ears and not adding enough weight or length for me to notice. Plus theyre quick and easy to clean and look right at home on Soviet rifles. A battlecomp or FSC would be more effective but also cost more than the rifle and look out of place. Next time youre at the range, do some rapid fire drills at close range, focusing on quick center mass follow up shots. This is where the side flip will be most noticeable and you may start seeing it in your semi's. Its not a huge amount of flip, often less than the amount of muzzle flip but it does slow me down enough to persue a solution. The slant comps are the fix I like for red rifles :)

CharlesT said:
I have fired many designs and calibers of rifles and never experienced this. From your description of the issue, I would imagine that this effect would occur on any style of rifle. I do notice however that all the rifles you mention are semi auto. Have you noticed this effect on a bolt action?

ct
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Will give it a try next time the SKS comes out to play. But I see now where you are coming from.

ct

supernova said:
Ive never paid attention as a fast follow up is not going to happen like it will with a semi. Cycling the bolt moves the muzzle around far more than the side flip I get with most semi's so even if it did happen it doesn't slow me down that tiny bit if I want to double tap or even just rapid fire. The slant comps reduce time between aimed shots quite noticeably for me while being very compact, easy on the ears and not adding enough weight or length for me to notice. Plus theyre quick and easy to clean and look right at home on Soviet rifles. A battlecomp or FSC would be more effective but also cost more than the rifle and look out of place. Next time youre at the range, do some rapid fire drills at close range, focusing on quick center mass follow up shots. This is where the side flip will be most noticeable and you may start seeing it in your semi's. Its not a huge amount of flip, often less than the amount of muzzle flip but it does slow me down enough to persue a solution. The slant comps are the fix I like for red rifles :)
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I'm not usually one for modded sks's but you did a nice job! You didn't take away from the over all rifle just subtle "side shifts". Good work! i like it.
 
D3TH_OVRH3D said:
Awesome looking SKS. Mind sharing some info one the shrouded rifle in the background in the first pic? Both are beauties!
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Looking like a Pietta PPS. 22, drum and stick mags available.

Supernova, have you ever posted how you got the bayonet off and moved the front site? I'd really like to do this and I'm not a complete ass when it comes to metalwork. Is it just cross pins and mallet work? Did you have to file a new pin slot on the barrel?

Local place still has some refurbs for about $170 I might pick one up to tweak on. Thanks.
 
Hi Mark
I used a CNCWarrior threading kit that I got from another member. They mfr the starter pilot (TAT) and outsource the rest of the tools.

MarkArma180 said:
Hey supernova, awesome build. I'm wanting to thread my sks muzzle 14-1 Lh and was wondering where you scored the die set? Also what starter die did you use. Thanks Mark
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