santanatwo
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Posts posted by santanatwo
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aside from my momentary math glitch, lets keep going with the math
three lugs at 16,000 pounds = ~ 5,300 pounds per lug.
two lugs at 16,000 = ~8,000 pounds per lug, an increase of 150% of force per lug.
you just exceeded the 125% "proof round" safety factor by about 25%
you can quit now...
"would generate approximately five times the design pressure of firearms"
Hhhrmmm. 300,000 PSI... yep, that'd probably destroy a bolt and turn it into shrapnel.
Moral of the story, don't put five times the powder into your .308.
Thanks for that advice Santanatwo!
Oh and
"Metal that is subjected to excessive force will form micro cracks, which get bigger over time until the part fails. In this case the part that will fail is holding ~50,000 PSI in a about ~0.33 square inched, that's ~150,000 PSI, pointed right at your face. IF you are lucky the top cover will blow off and some shrapnel will go flying, and maybe you will have some cuts and burns, if you are unlucky you will die, or worse, an innocent person who was unaware of your "monumental mistake of epic proportions" will die. (words fail me)"
50,000 pounds per square inch.... on a .33 square inch surface, is still 50,000 PSI... But probably only 16,500 pounds of pressure pushing on the bolt since the area is .33 square inches. According to you.
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eight tons of force, being held back by three little lugs, and you want to go cutting out a third of the strength?
what could possibly go wrong.
The point here, gentlemen... is that you should not go cutting off your bolt lugs...
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"would generate approximately five times the design pressure of firearms"
Hhhrmmm. 300,000 PSI... yep, that'd probably destroy a bolt and turn it into shrapnel.
Moral of the story, don't put five times the powder into your .308.
Thanks for that advice Santanatwo!
Oh and
"Metal that is subjected to excessive force will form micro cracks, which get bigger over time until the part fails. In this case the part that will fail is holding ~50,000 PSI in a about ~0.33 square inched, that's ~150,000 PSI, pointed right at your face. IF you are lucky the top cover will blow off and some shrapnel will go flying, and maybe you will have some cuts and burns, if you are unlucky you will die, or worse, an innocent person who was unaware of your "monumental mistake of epic proportions" will die. (words fail me)"
50,000 pounds per square inch.... on a .33 square inch surface, is still 50,000 PSI... But probably only 16,500 pounds of pressure pushing on the bolt since the area is .33 square inches. According to you.
You're right, my bad, 16,000 pound of force, not pounds per square inch. That's 16,000 pounds pushing on the bolt carrier, sending it at your eye.
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"Back in 1965 the Vietnamese put gum paste in .223 rounds and air dropped them to soldiers. This is what made the M16 such a failure."
~Abraham Lincoln
The bolt and pieces of an exploding AK-47 receiver would typically be projected backward into the head of the individual firing the rifle.
I hate using wikipedia, but here you go, other sources are available.
So don't roll your eyes at ME, son.
you will only EmBareAss yourself. 
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"Back in 1965 the Vietnamese put gum paste in .223 rounds and air dropped them to soldiers. This is what made the M16 such a failure."
~Abraham Lincoln
no, the US army changed to a ball powder that didn't burn right and left residue that clogged up the M16 action, nice try though. When they went back to the original powder the problem was solved.
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pic of bolt with 3rd lug completely ground off
high five on your gun not blowing up (yet).
How many rounds did the russians put through their test guns that made them decide lug #3 was a good idea. Hint: it's not the number of lugs that matters, it's the strength of the lugs x number of lugs that matters.
So, do you intend to ever sell this gun? are you going to pass it on to your kids? what if they sell it?
You'll be long dead, so I guess you don't care if someone 50 years from now dies while shooting that gun. Thank you for posting pics so that we may learn from your shocking mistake, and so we can all keep an "eye out" for future shenanigans from other "home" smiths at the used gun table at our local gun shows. You have opened my eyes, and I thank you for that. If someone dies from this, may god have mercy on your soul.
The point, is that you have no idea what kind of metal that bolt is made of, nor do you know what heat treatment was used for that type of metal, you do not know what kind of pressure it can take, nor for how many rounds before it blows up.
Metal that is subjected to excessive force will form micro cracks, which get bigger over time until the part fails. In this case the part that will fail is holding ~50,000 PSI in a about ~0.33 square inched, that's ~150,000 PSI, 16,000 pounds of force pointed right at your face. IF you are lucky the top cover will blow off and some shrapnel will go flying, and maybe you will have some cuts and burns, if you are unlucky you will die, or worse, an innocent person who was unaware of your "monumental mistake of epic proportions" will die. (words fail me)
I see how some people have modded the third lug to shape it so it doesn't gouge holes in cartridges. ok, fine, hope you are careful about taking off to much...Keep in mind russian ammo is steel cased, and is not so easily torn up. Using brass ammo a poorly shaped lug obviously can tear a hole in it. Perhaps Ivan forgot a step in the machining and left a sharp edge.
My saiga does dent the cases pretty bad. I don't like it, and obviously I can't reloaded them repeatedly, I figure one or two reloads is all I can safely get out of them. But it does work, functionally perfect
The reason that the "thread that shall not be mentioned" ended in a shit storm of epic 72 font, is because people who had no clue what "they" were doing were advocating/doing something that knowledgeable people knew would end in injury and death, and when educated of their ignorance of metalugy...some of them continued to advocate stupidity... now, ignorance can be cured, but apparently stupid is permanent.
IT is your choice, to educate yourself... or become a Darwin Award winner.
P.S. Your gun is toast, no-one sells replacement bolts at this time. I suggest parting it out. I'd be willing to buy that bolt off of you to keep it out of the hands of the public.
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snip
that's a neat video of the ground, I must admit, in the face of such clear evidence I am forced to concede the point.
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During Vietnam, the USA special forces had a program where they planted overpressure 7.62x39 ammo in magazines and ammo boxes, just one round in a case, or in the middle of a mag, and when the round went off, it sheared off the trunion/bolt lugs, and the carrier went through the right eye of the NVA soldier.
facts, how do they work?
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I just ground my bolt down
how many rounds downrange? 100? 500? what happens when it gets to 5000 rounds? ever hear of metal fatigue?
You won't own that gun forever, some day you will die and some innocent person will be putting round #000 downrange, ormaby they get some bad ammo with over preasure issues like that indian 308 from a few years back....Please don't ever sell that gun. and before you die, please destroy the bolt and throw it away, before some innocent person dies.
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If that part fails, it doesn't blow your hand up, it sends the bolt carrier through your right eye and into your brain and you die.
However cutting off that lug will make your rifle cycle 15% faster, which is deffinitely worth the risk.
OR better yet, mod it and sell it at a gun show without telling anyone what you did.
Seriously guys? talk about some bubba smithing...WECSOG is one thing, but this is redickalass
I'll be sure to only buy factory new saigas from here on out, or visibly inspecting the internals before pulling the lever. No telling what you might run into these days.
(Just when I think you couldn't do anything dumber, you go and do something like this, and TOTALLY redeme yourself!)- Dumb and Dumber
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material concerns
Well, looks like you seem to have a pretty good grasp on the situation, answered your own question with a question, gratz.
Do you know what kind of materials each of those various countries used to construct their rifles? Not just the bolt but the trunion also? And how that type of metal was annealed and tempered?
No?
Ok, then any further speculation is useless.
Keep in mind that quite a few British Enfields were modified to chamber 7.62 nato, which will also chamber 308 which has been shown to be beyond the safe limits of (not the design but) the material from which the rifles were constructed. The Indian 308s are built visibly similar but with stronger steel.
P.S. You'll put your eye out kid.
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p.s. it doesn't even recoil, with that 4 slot krink brake, it just vibrates slightly, accompanied by a thunderous BOOM!!!!!!... YEAH!!!!!
and from the original pic, sinc ethey both visited the same guy...
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I took the measurement for the gas port from the 16 barrel that I took off. I see it was way to big. I'll be needing a new barrel anyways though, the smithy I had trim down the barrel did NOT do it to my specs, as he removed the face of the breach, lik eI told him NOT to. I went with it anyways, but it lets the extractor slam the barrel on an empty chamber.... and aside from the ding building up on the breach face, the extractor will be getting weakened and eventually break, I am sure... so next time I'll be buying a lathe and doing it myself. I thought I could get away with the way he did it, but it isn't going to fly int he long term, and extractors are a bit hard to come by. The good news was that I didn't need any kind of feed ramp cut ont he barrel like the factory had, as the bullet goes right into the chamber. very nice.
Not exactly back to square one, but I guess the next time I'll be doing it the RIGTH way, correct size gas port and proper breach face.
I haven't posted pics but I nickel plated all the parts that aren't attached to the barreled receiver, it's hawt! I'll see if Ican find my cord to my cell phone so I can download them.
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looks awsome, I'll be ordering a few of these soon.
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totally normal, the russians measured their 7.62 on the lands
Americans measured the 7.62 in the grooves.
thus the russian 30 cal is actually slightly bigger. (IE. closer to the american 32 ACP)
The 7.62x51 being an american bullet is slightly smaller diameter than the 7.62x54R bullet
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awsome, I can't wait to get a mag I can bling out to match, my bling 243 conversion...
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Instead of a makeshift buffer I would try a heavier spring (wolf sells'em). It seems even though the 308 spring is stiffer than say a Romy G those brand new stiff wolf springs really slow down your bolt. Also, I would maybe think about increasing the weight of the bolt carrier, maybe turn urself a new piston with a thicker shaft etc. I say this beause bumpers are hard on your rear trunnion and as nice as that build is, the less stress the better. Another idea might be to somehow silver solder and partially plug the gas port. Just a thought. Regards
well, this was the cheaper sollution, just screwing in the piston deeper. And it worked, it cycles perfect now. ejects them about 15 feet to the right.
but I had considered a custom thicker piston, to add weight.
I didn't know wolf sold heavier springs for the AK.
There aren't to many good sollutions when you drill the port to big.
1/16" is about .0612", factory is 0.055" acording to my calipers.
not much of a difference. I suspect the smaller bore or perhaps the higher velocity of the bullet made the difference, along with the longer barrel made for some energetic ejection, top say the least.
so, in the future, anybody want to do this, start off smaller than 1/16" for your port.
I'm guessing 3/64 would be ideal, but start at 1/32 to be safe.
I knew better than to start at the size I thought it would be. but it was late on a friday night and I wasn't wanting to wait till monday to finish the build... doh!!!
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I came up with a novel sollution.
I screwed the gas piston in as far as I could without limiting carrier travel, (about a 1/2") this reduced the pressure inthe gas block and slowed bolt carrier travel, now it ejects normaly, and does not rip off case rims, also the cases aren't getting dented as bad when the bolt rides back over them. (now it's just a little ding, instead of a 1/4" dent.
next time I'll use a 1/32" drill bit to start with, then, IF it doesn't cycle, go up to a 3/64"
1/16" is just to big for that setup
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Very nice conversion!! Awesome workmanship.
What was the original barrel length if you don't mind me asking? I am looking for a long 308 barrel for my 308.
16" sorry.
I believe the gas port is to big, cause I used a 1/16" and I should have used a 3/64. not much difference, but enough.
the carrier is hitting the recoil assembly hard enough to cause a mark. I'm gonna have to install piece tire sidewall to act as a buffer.
bummer.
next time I'll use a 3/64 for the gas port.
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As you may know, a 243 winchester cartridge is simply a necked down 308, a smaller faster bullet, FTW
Mag compatability is a non-issue.
I just finished this last night, It started out as a sporter saiga 308 (7.62 X 51mm).
I removed the rear trunnion and installed a side folding bulgarian stock and USA pistol grip. With a G2 trigger group.
Then, converted it to 243 Winchester with a brand new 22 inch stainless steel barrel. (got it off gunbroker, for cheap, and lathed it down to fit)
It has a flash hider and bayonet lug , of course.
Range Update
It ejects strongly, and like a lot of other saigas, it seems to damage the rim of the soft brass casings about every 5th round, and I think the bolt needs that mod to prevent severe case damage from the (bolt carrier?) denting the shoulder of the casing. I don't know exactly were to mod, anybody know?
It groups nicely, I was getting about 1" inch at 30 yards. But It was me, not the gun, I was wobbling a bit, cause of the shitty range I was at didn't have a good bench.. I'll bet the gun can do better than 2 inches at 100 yards, If I do my part. Mostly it was just function test. And it worked perfectly.
A few of the brass casings had the rim ripped off, I suspect it is normal, as I have seen factory 223 saigas do the same thing (soft brass). It ejected fine though, even though the rim got ripped off a few times.
And you can see where the ejector hit the head. again, I have seen this on normal guns, so I'm not concerned.
I doubt my gas port is to big, as it's at 0.065 (1/16"), as opposed to factory 0.055 but that was the closest size I could get here in the city, as 3/64" would have been to small.
IF I do this again though, I'll try a 3/64 first, just to see. I plan on doing a 24" barrel next time, so a 13/64" should work fine, due to the longer barrel and increased gas linger time.
Anyways, the gun works fine and other than damaged rims and dented shoulders..... it's all good.
I didn't even need to make a ramp on the barrel, just cut to extractor depth and GTG,
I'm really happy with it, and I'd like to try some light weight loads. The 100 grainers work good, but they don't have the spectacular velocity that was my main reason for doing this conversion. I'd like to find some ~55 grainers, and hand load them, just to see what it'll do.
Vaporization of metal targets was my main goal here, as well as a wicked long range deer gun.
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soon to be converted to 243
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Just an update, I got my new mag from surefire, after mailing my old one in.
The new mag feeds great,
thanks surefire.
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IF it has a metal insert to keep the forearm from melting off the gun during rapid fire... then it looks like a great deal.
I ahve seen to many plastic forearms get melted....
The original saiga forearm has metal where it touches the gas block pin.
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After chewing out SaigaNoobie's ass over wanting to grind of the third lug on his saiga 308, I would feel negligent if I didn't point out the fact that you are removing metal from at least one locking lug, possibly two, including the third lug... I don't ahve a saiga 223 in front of me right now, but I am familiar with this conversion. I dd one myself a few years back.
In my mind, this suddenly does not seem very safe.
3rd lug Saiga vs PSL Bolt.
in Saiga .308
Posted
I really can't believe this is a subject that even needs to be argued... seriously?