If you have a rotating table you should be able to make one, even without indexing. Heck, I think my indexer (doesn't rotate) could be used to build one. Just need to heat treat it properly. I would use 4340, but 4130 may be good enough?
Might as well make it a 3lug design while were at is and longer so we dont have to move the trigger guard. a m76/77 style bolt but with three lugs some thhing that will handel 65,000 Psi would be nice. I wonder what a sagia 308 will actually handel?? It can be done and Ive looked at doing it but if I were to do it Id want to make a bunch of them and I just simply dont have the funds for it or the insurance to sell them. I am starting to see more and more guys with CNC equipment talking about doing bolts and trunions. Turbothis ahs been playing with a CHC mill on the AK forum and he has made some cool looking stuff he was talking of doing 19mm trunions.
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The Saigas and Veprs had to pass CIP proof testing which is 125% of standard max chamber pressure. They first tried a two lug 308 design that wouldn't pass CIP proof testing.
Saiga .308 bolts are in short supply. That is why I use a Bulgarian 5.45 bolt in my 7.62 NATO AK. Although I did have to open up the bolt face, and dremel the extractor a little.
The 308 Saiga bolt is a different design. A standard AK bolt may hold up to a bit of shooting, but it might not. When firearms are proof tested they are placed inside a steel container.
Well...I happen to talk to some of their designers and specifically mentioned this to them on a side note and they were very quick to correct me that the pressures were fine and that the reason they added that extra lug was to try and squeeze a little more accuracy out of the .308. I'll find out more on my next visit with them, but until I can see the actual "publication" and from what source...which I will ask them about and have them verify...I am going to remain skeptical. I have seen a few .308 builds that do just fine on hot handloads without a third lug. How many does the M76, PSL, .308 M90s have???
Those two lug models have heavy bolts. One of the design features of the AK is the bolt to bolt carrier weight ratio. Increasing the bolt weight with the same bolt carrier weight in theory would reduce reliability. The three lugs can't have anything to do with accuracy. The reason some bolt actions have three lugs is to reduce the size of the lugs so the bolt doesn't have to rotated as far as a two lug bolt with larger lugs. The increase in lugs in the AK is to handle more bolt trust from the larger cartridge.
During the designing of the Beretta AR70 and Sig 540, both Beretta and Sig teamed up at first to design one rifle. The design team included two American engineers. The Americans wanted a multi lug bolt like the M16 because they claimed it was more reliable in design because the bolt didn't have to rotate as much as having larger bolt lugs. Both Sig and Beretta rejected the multi lug bolt design because they claimed it would hurt accuracy by not being able to always get even loads on all of the bolt lugs. They both went went to two lug bolts for "accuracy", because they felt even lug contact was possible with two bolt lugs. I would have rejected the mutli lug bolt due to not always being able to have even bolt lug contact, but my reason would be the strength would be weaker with higher bolt lug loads on less then all bolt lugs.
flat out ask them how much pressure a AK trunion is rated for or will proof test at. It would be the first thing Id ask if i ever met someone in the know
Well stay tuned guys...as I may be able to get a monthly or weekly Q&A post type of deal with some of THE guys...you guys could post a question or two that I take to them and then I come back and post their responses. They might think it as fun too. We'll start with the .308 bolt and WHY it has a third lug and HOW MUCH pressure can it and the trunnion take. I'll start a new thread and post this question and their answer after I talk with them. Sound good?
I am finally going to be able to make this a reality. Talked to the BIG bosses in Russia and they agreed. I'll be putting this on my website that is currently being developed as an "Experts Corner" or something like that. I'll let you know when it's up, but the address is Red Dragun Weapons | Coming Soon. We just finished importing some of these:nanabang::
Top two are my crappy photos (which will soon be better) and bottom one is for better reference.
It shouldn't be too hard to setup. I think they will find it fun and interesting too. We'll see what they say though and if they are in I'll make it happen. By the way I think the average worker there makes about $500 per month.
One problem is in most of Europe and other countries any gun part "exposed" to chamber pressure is controlled. The other problem would be selling parts that effect headspace usually aren't sold by commercial gun makers.
Well its almost christmas and I dont know what its going to end up as but my 9 year old is going to get aa big box of misc gun parts. The plan is were going to do a Father/Son build of a undecided calibure. the objective will be a light weight sporter that is carryable by a young hunter it will need light recoil but have at least 2600 FPS velocity with a 100 grain bullet or bigger and be 6mm or bigger. Im thinking a Yugo trunion with a opened up 5.45 bolt that will shoot some thing from the 308 Win line of brass. I have a remington 243 take off barrel as well as a 308 barrel. he is still pretty small so Im leaning toward the 243 loaded light. I have decided that i will not go over 49,000 PSI on the ammo with a two bolt trunion. I am thinking a longer than normal blank with a extended bolt will allow a large gloves on trigger guard. I want a push button saftey. Im thinking of a drop out trigger housing and some other cool ideas that I have had in the back of my mind. I have untill next thanksgiving to get it built and and get him shooting well enough shoot from a stand on white tail. Im not sure of the legalitys of a minor bending his own flat so ill have to look into it. I was actualy thinking of a multipul barrel assembly set up with a .223 varmit, 243, .30 an a .444 in a cool custom case that would cover all hunting scenerios he might find in the future. i really wish i had a 3 lug bolt for this build . Im thinking of making this as custom as possable with the finest work i can muster.
I keep thinking the 300 savage may be the safe bet but the damm brass is pricy and not avalaibe surpluss like the 308 win. I really hate the Idea of my kid getting a hold of a full blown 60,000 Psi round accidentaly and possably getting hurt. I could alway rebate the brass so and use a standard bolt and then there is no way a bolt can close on normal ammo. but that will reqire a fair amount of work and im hoping to get my son a chance to do some serious shooting and that means a lot of brass. if it was just deer hunting 40 rounds would last 5 years.
i read a interesting article about how a rough or sanded chamber VS a polished one can have significnatly lowere bolt thrust but at the same time the brass will get worked more and shorten reloading life. stared maging me thing about a groved chamber to keep the round from going back ward into the bolt so hard. is this what the futed chambers do on other types of weapons??? either way i will not have a polished chamber. Ill try to find the link to the article.
It's bad enough buying brass for 7.62x39. Hopefully 223 brass will be easier and cheap to buy. I do load a lot of 7.62x39. The brass doesn't last long though.
Hello 1biggun,
You got the wrong area !!! Area of a circle = 3.14 x Radius X Radius. That means first you have to divide the diameter in half to get radius.
The pressure formula is fine ie: Pressure in PSI x Area in square inches = Force on the bolt face in pounds.
Keep all the measures in their inches or pounds to be consistent (and correct).
Another hint is to use decimals rather than fractions. So: .5 inch x .5 inch = .25 inches (squared)
Then .25 inches (squared) x 3.14 = .785 square inches.
Hello 1biggun,
You got the wrong area !!! Area of a circle = 3.14 x Radius X Radius. That means first you have to divide the diameter in half to get radius.
The pressure formula is fine ie: Pressure in PSI x Area in square inches = Force on the bolt face in pounds.
Keep all the measures in their inches or pounds to be consistent (and correct).
Another hint is to use decimals rather than fractions. So: .5 inch x .5 inch = .25 inches (squared)
Then .25 inches (squared) x 3.14 = .785 square inches.
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