AR-15 Bolts
- Thread starter OneWound
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maxxhavoc
Member
Probably not.
You will need a heavier BCG to convert the action to direct blowback, You will also need heavier buffer spring and weight. There is not enough pressure in a 45ACP to cycle a standard gas AR.
It would be easier to start with a 9MM BCG if you were going to create it yourself. It already has the mass, although you would need to tweak the weight.
Of course .45 BCGs, springs, magwell adapters, and barrels are out there if you look (and have $$ to spend.) Palmetto State Armory has already said they were looking at building out .40 and .45 ARs in the next year or so. I want the same thing, but I am going to wait. I built a 9mm AR 4 months before PSA made a kit at $400 cheaper than I spent.
You will need a heavier BCG to convert the action to direct blowback, You will also need heavier buffer spring and weight. There is not enough pressure in a 45ACP to cycle a standard gas AR.
It would be easier to start with a 9MM BCG if you were going to create it yourself. It already has the mass, although you would need to tweak the weight.
Of course .45 BCGs, springs, magwell adapters, and barrels are out there if you look (and have $$ to spend.) Palmetto State Armory has already said they were looking at building out .40 and .45 ARs in the next year or so. I want the same thing, but I am going to wait. I built a 9mm AR 4 months before PSA made a kit at $400 cheaper than I spent.
MachIVshooter
Member
You would have to design it in such a way that the .45 bolt was rigid in the carrier. As stated, .45 ACP lacks the gas pressure and volume to cycle an AR, so it would need to be a blowback design.
Might have to play with buffer weights and springs, but yeah, as long as the reciprocating mass and spring rate were properly calibrated.
Might have to play with buffer weights and springs, but yeah, as long as the reciprocating mass and spring rate were properly calibrated.
maxxhavoc
Member
This is a good place to start looking at differences:
http://thegunwiki.com/Gunwiki/AnalysisAR9mmRRA
http://thegunwiki.com/Gunwiki/AnalysisAR9mmRRA
Thank you all. I did a little research, and while I don't know how I'm going to do it I know it's going to be blowback. I'm thinking the best way (going off of what someone else did) is to buy a replica thompson sub barrel, have it threaded for a 9mm upper. Have this 9mm upper modified to accept a .45ACP bolt from oly. Then build a AR45 lower to accept grease gun mags, or buy an adapter (which will probably end up happening-ORRR I'll make it!).
MachIVshooter
Member
That's a lot of trouble and expense to obtain something that can be purchased readily.
http://www.hinterlandoutfitters.com...o-collapsible-stock-black-finish-p-49057.html
http://www.hinterlandoutfitters.com...o-collapsible-stock-black-finish-p-49057.html
pjeski
Member
I have oly pistol uppers in 9mm and .45acp. I like that they run ona standard AR lower with no modifications. They use proprietary mags that fit a standard mag well. They run fine on my M16 lower as well. (You have to specify a full auto BCG if you want that feature).
jmorris
Member
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- Sep 30, 2005
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A 458 socom bolt would fit the 45 acp.
Also found this.
http://www.olyarms.com/shop/parts/bolt-and-carrier/ar-15-parts-pistol-cal/pc26-45.html
And this
http://firearmsdesigner.com/?p=378
Also found this.
http://www.olyarms.com/shop/parts/bolt-and-carrier/ar-15-parts-pistol-cal/pc26-45.html
And this
http://firearmsdesigner.com/?p=378
Pjeski, does the ID on the .45ACP upper match that of a .223 (I'm guessing not, but it doesn't hurt to check)? If no, whats the different in ID of your 9mm and 45ACP upper?
jmorris, your second link is good but it wouldn't have enough mass, according to previous posts, to be able to work as a blowback system. As well, the idea to use oly's 45ACP bolt has crossed my mind more and more because I realize who I am and what I can't do legally (to their rules, not state laws) on a college campus!
jmorris, your second link is good but it wouldn't have enough mass, according to previous posts, to be able to work as a blowback system. As well, the idea to use oly's 45ACP bolt has crossed my mind more and more because I realize who I am and what I can't do legally (to their rules, not state laws) on a college campus!
Zach S
Member
OneWound, AR15 uppers have the same ID regardless of caliber.
I've seen ARs built in various calibers using a stripped 9mm upper to get the old school look of a slick side with the flexibility of a flat top.
I used a 9mm upper when building my .22lr AR15 around a conversion kit, just so I would have a brass deflector.
I've seen ARs built in various calibers using a stripped 9mm upper to get the old school look of a slick side with the flexibility of a flat top.
I used a 9mm upper when building my .22lr AR15 around a conversion kit, just so I would have a brass deflector.
Another stupid question. Taking what Zach just told me, theoretically I am able to take a .45ACP bolt, put it in a standard AR upper receiver, put in a .45acp barrel (assuming threads match, as well as timing is correct), and have a functioning .45ACP gun? This excludes the magazine well of course.
Caliper_Mi
Member
That's pretty much it. Barrel, bolt, magwell insert for whatever type of mag you're using. Possibly you'll need to tune the buffer weight for reliability and depending on how hot your ammo is.
Gas operated (direct impingement) 45ACP uppers do exist though: http://www.rmwxtreme.com/#top
ARFcom has a pretty extensive thread on 45acp conversions as well. Fair warning, I think the thread is older than many of the commercial solutions on the market today: http://www.ar15.com/forums/t_3_15/345390_.html&page=1
Gas operated (direct impingement) 45ACP uppers do exist though: http://www.rmwxtreme.com/#top
ARFcom has a pretty extensive thread on 45acp conversions as well. Fair warning, I think the thread is older than many of the commercial solutions on the market today: http://www.ar15.com/forums/t_3_15/345390_.html&page=1
pjeski
Member
It's a standard AR upper but has a hole drilled and a wire wound (spring) ejector installed. I don't think I'd want to run the bolt in a non-oly upper, but I imagine you could buy and install the ejector yourself.
pjeski
Member
The thread pitch is 1/2-28. The thread length is short like a pistol, not long like some AR barrels. There is a bit of a shoulder to the threads, so it may or may not work with all suppressors. I have a TROS three lug adapter on mine.
The .45acp has an odd thread, 5/8-24. A TROS .578-28 adapter allows me to run my .45acp cans on it.
Both barrels are, IIRC 6-1/2" long.
pjeski
Member
Google says Oly's 9mm rifle uppers have a 1/2" x 36 thread, but I don't know what you would do with that thread except put an adapter on it. My 9mm pistol upper has a 1/2 x 28 thread, and since that is the standard for 9mm suppressors, I'd rather have it that way.
pjeski
Member
Ah. It's a standard upper and barrel nut.
pjeski
Member
As far as I can tell, yes. They are completely standard uppers except for the ejector. Oly also makes them in .40 and 10mm.
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