Question about 450b pressures

[vz58]

I cant seem to find a definitive answer on SAAMI pressures for the factory 450 bushmaster loads. Can someone point me in the right direction?

[pitted bore]

I cant seem to find a definitive answer on SAAMI pressures for the factory 450 bushmaster loads. Can someone point me in the right direction?

vz58-
Wildcatter has stated in posts here and on the old calguns thread that Hornady loads the ammo at SAAMI pressure of 38,000 psi. I suspect he's probably correct, because he developed the cartridge.

If I'm incorrect, he'll be along and make it right.

--Bob

[wildcatter]

Bad Bobber has it correct, 38,000 psi "sammi"..

..t

[vz58]

Thanks. I have a green mountain barrel blank I have spun to fit a Yugoslavian AK receiver and was just curious. I have built one in 45 win mag but there are occasional feed problems with the very short cartridge. The 450 bushy length should help out.

[Hoot]

Thanks. I have a green mountain barrel blank I have spun to fit a Yugoslavian AK receiver and was just curious. I have built one in 45 win mag but there are occasional feed problems with the very short cartridge. The 450 bushy length should help out.

[pitted bore]

Thanks. I have a green mountain barrel blank I have spun to fit a Yugoslavian AK receiver and was just curious. I have built one in 45 win mag but there are occasional feed problems with the very short cartridge. The 450 bushy length should help out.

Pictures? Please! Pretty please!

--Bob
edited to repair image link

[vz58]

The only pics I have of it are these, they are older as I was building it. I have used it for hunting (but it is not "finished" as in pretty.) Since the 3rd or 4th round is my hang up I kinda let it drop as far as making it pretty.












A series showing how it *Should* be controlled feed.







Homemade magazine




Here it was about 2 years ago, I had to move the mag forward and I tried to add a BHO to it and flubbed the magazine. Also I was carving a stock that would raise the comb for the cobra red dot.






the gas block


After moving the mag forward



This was an experiment to see if it could work. it can but a longer cartridge would be better and the ability to use a commercial magazine would eliminate the feed isues I have had with the 45 win mag.

[Hoot]

You weld the barrel in so it can handle the energy from a 450b?

Hoot

[vz58]

That receiver is a Russian type III threaded receiver. The barrel was pressed into a bushing made of 4140 steel and then pinned, threads turned on the bushing and then installed. I have had concerns of the higher pressure in a Thomson (45acp Barrel) so the loads used after initial testing are light. I Have successfully hunted (eastern white tail to 85 yards) in the brushy area near here with 185 grain XTP. I have clocked various loads (the hottest test load was near 2650! fps) If you run them too hot the jacket comes apart. The hot loads were trying to find signs of over pressurization and they did show primer flow.

My hunting load runs at 2010 fps and has very mild recoil. Head space has never changed.

Its a good gun but I can build better. I had wanted to go with the 45win mag because I had about 300 pieces of brass for it and the 450 was still pricey.

I will not weld it in on the Yugo, I dont like welding on a barrel, I know people do it but not me.

On the 450 yugo it will be the press and pin type trunnion. (Yugos use the stronger RPK trunnion designed for strength and in the Yugo's case, grenade firing)

Where it presses into the trunnion it is .9075" which steps out to .990" under the hand-guard. the gas block is at .865" right now and the portion from gas block to muzzle is .790"

I do not have a 450 in an ar platform so I dont know what the various diameters are for its barrel. I wanted to leave plenty of meat on it until I found those dimensions.

Also I plan on fluting it (just because I can) under the hand-guard and on the exposed portion of the barrel. If I would take the time to build a mounting I could spiral flute it on the CNC mill but never can find the time.

[wildcatter]

Way cool, looks like a mag of your own design??

I have used M1 Carbine Mags with great success. Hey! Come to think of it, didn't someone build M1 Carbines to shoot the 45 Winchester Magnum?? I think he was a dead ringer for Brad Pit, or was it Shemp Howard (For you guys to young http://www.havelshouseofhistory.com/Howard,%20Moe.jpg), I can't remember?

Assuming that your conversion will hold the pressures of the 450b, you might want to get some of those AK 223 Mags, that should be the trick for an AK..

..t