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Awesome
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also looking at this im not sure how much id trust it, while it is possibly to just design the trunnion to have a forward threaded extension for a barrel nut the hard part becomes headspacing.. that barrel does NOT contain the locking lugs for the bolt to lock into so if for some reason it doesnt get tightened down completely you may not have headspace

ive designed a semi-quick, or at least toolless change barrel for an AK that involved a threaded trunnion and a shoulder-less threaded shank barrel that threads into the receiver over a headspacing gage and has a threaded barrel nut tightened down over top, like a savage barrel so returning the barrel to zero after removing it and putting it back on wouldnt be hard, still not ideal

quite simply the simplest solution would be to just thread the trunnion itself.. sure, the receiver isnt thick enough to handle the stresses from firing and your holes will egg-out where the trunnion wont fit anymore, but that doesnt mean you couldnt weld on a couple side plates on the sides of the AK receiver to reinforce it where this would no longer be an issue.. at which point doing a barrel change on an AK becomes an almost identical task to doing a barrel change on an FN SCAR

i do think a "multi caliber" weapon is a bit gimmicky though, add extra parts that need to be maintained, or replaced or have the potential to break, if i want an AK in another caliber, i build one in another caliber
 

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Discussion Starter · #5 ·
i do think a "multi caliber" weapon is a bit gimmicky though, add extra parts that need to be maintained, or replaced or have the potential to break, if i want an AK in another caliber, i build one in another caliber


I agree the more i think about it, would have to see more.
 

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Awesome
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I agree the more i think about it, would have to see more.
yeah.. take the AR for example.. lets say you want to go from a 5.56 to 300 BO.. well, these are clearly different rounds, 300BO will be a slower, heavier round resulting in more back pressure as the dwell time is shortened due to lower velocities and the larger bore will result in a different pressure curve.. so even though you can swap barrels and theoretically it SHOULD work.. for optimal reliability youd have to toss in a heavier buffer, heavier buffer spring, and adjust the gas system...

so much easier to simply have a second rifle properly tuned for the other cartrdige.. especially when you realize how much added labor it actually entails beyond a simply barrel swap.. and for that matter, what calibers are you going to get in an AK?.. i mean, you swap froma 7.62 barrel to 5.45 youre going to need a new bolt and the mags wont even fit.. if you go from a 5.56 to a 5.45 or 300 BO there are magazine differences here and variations in the bolt face.. the best you could get from a "multicaliber" AK is one that can go between 5.45 and 5.56, but with 5.45 being lower pressure, doing this on a '74 gas system will result in higher carrier velocity when going to 5.56
 

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Discussion Starter · #7 ·
yeah.. take the AR for example.. lets say you want to go from a 5.56 to 300 BO.. well, these are clearly different rounds, 300BO will be a slower, heavier round resulting in more back pressure as the dwell time is shortened due to lower velocities and the larger bore will result in a different pressure curve.. so even though you can swap barrels and theoretically it SHOULD work.. for optimal reliability youd have to toss in a heavier buffer, heavier buffer spring, and adjust the gas system...

so much easier to simply have a second rifle properly tuned for the other cartrdige.. especially when you realize how much added labor it actually entails beyond a simply barrel swap.. and for that matter, what calibers are you going to get in an AK?.. i mean, you swap froma 7.62 barrel to 5.45 youre going to need a new bolt and the mags wont even fit.. if you go from a 5.56 to a 5.45 or 300 BO there are magazine differences here and variations in the bolt face.. the best you could get from a "multicaliber" AK is one that can go between 5.45 and 5.56, but with 5.45 being lower pressure, doing this on a '74 gas system will result in higher carrier velocity when going to 5.56

Yea i don't like swapping upper receivers, make a given weapon for one caliber. Other calibers Molot offers are 6.5Grendel, 7.62x54r, .308, 5.56, .243, .30-06, i think thats all lmao.
 

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Awesome
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well, youre probably not going to get 7.62x54R and 308 in the same receivers as you will the other calibers since either the mag catch has to be pushed back to clear room or the trunnion has to be heavily modified, or the whole receiver needs to be stretched

as far as 6.5 grendel, sure it fits the 7.62x39 bolt face but thats about it.. you would need a removable magazine adapter to go back and forth using poorly constructed AR-15 mags which are nothing but a compromise given how narrow the AR-15 magwell is and how fat 6.5 grendel is

it all sounds like a fantastic way to waste money and end up with a **** weapon in any caliber
 

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Two things happen with multi caliber rifles.

First and most commonly the company never comes out with the conversion kits promised so you end up with a more expensive single caliber gun or second no owner of multi caliber rifle has ever purchased the parts (if available) to swap between calibers and shoot both.

It is sort of like a para cord bracelet, everybody wants one but nobody in history has ever used one for anything other than a prepper fashion statement.
 

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I tried the conversion thing with a number of things over the years. Always ended up with the gun in the configuration I liked the most, and everything else sat on a shelf. Lots of money just sitting there doing nothing. Could have bought another complete gun in a lot of cases.
 

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That too.

That was also another issue with the conversions. A number of cases of ammo for each caliber change I wasnt using.

I did make out there though, as it was right around the time of Obama getting in and that first big ammo scare nonsense. Cases of .40 and 357SIG that I paid $250 a pop for, were selling for $400-600. I made out real well selling them off. :thumb:
 
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i hear a lot of people touting the SCAR as a multicaliber weapon.. but i cant really see FN making any other calibers for it and if they do i rarely see people spending $1000 on the new barrel so they all just sit around in 5.56 or 308 doing nothing more than what you could get out of an $800 AR15/10

and then the military makes a big blunder on the P320 touting its "multicaliber" capabilities.. tell me, you ever see a soldier switch from a 9mm to a 40 during combat?.. lmao, no, this doesnt happen.. multicaliber anything is generally just a massive waste of time and money
 

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Discussion Starter · #14 ·
i hear a lot of people touting the SCAR as a multicaliber weapon.. but i cant really see FN making any other calibers for it and if they do i rarely see people spending $1000 on the new barrel so they all just sit around in 5.56 or 308 doing nothing more than what you could get out of an $800 AR15/10

and then the military makes a big blunder on the P320 touting its "multicaliber" capabilities.. tell me, you ever see a soldier switch from a 9mm to a 40 during combat?.. lmao, no, this doesnt happen.. multicaliber anything is generally just a massive waste of time and money

My wife likes her M4forgery & her Glock 19, while she doesn't mind my AKs she much prefers the AR15 due to her time in the Army. She would prefer to buy 9mm/5.56 & not have to buy 8 different calibers lmao, like me haha! Thats why I've been debating adding .300 Blackout to my collection, with .300 blackout i can use spent 5.56 cases for my brass and .308 bullets are very common. IF i really wanted to i suppose i could collect all of the lead/sift sand at the range then make my own .308 bullets lol. Not to mention i can hunt out 200yds(effectively) with .300 blackout as well.
 

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My wife likes her M4forgery & her Glock 19, while she doesn't mind my AKs she much prefers the AR15 due to her time in the Army. She would prefer to buy 9mm/5.56 & not have to buy 8 different calibers lmao, like me haha! Thats why I've been debating adding .300 Blackout to my collection, with .300 blackout i can use spent 5.56 cases for my brass and .308 bullets are very common. IF i really wanted to i suppose i could collect all of the lead/sift sand at the range then make my own .308 bullets lol. Not to mention i can hunt out 200yds(effectively) with .300 blackout as well.
if you want my advice just switch to 5.56, it has a lot more range, the higher velocity, lighter round means flatter trajectory, quicker followup shots, easier to lead moving targets, ammo is lighter, easier to carry lots of.. there are just so many more benefits to it than you get from a heavier, slower projectile.. plus a 55 grain at 3100-3200fps will go through a level 3 steel plate. you'll NEVER get 7.62x39 going through hard body armor
 

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that's like, your opinion
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Two things happen with multi caliber rifles.

First and most commonly the company never comes out with the conversion kits promised so you end up with a more expensive single caliber gun or second no owner of multi caliber rifle has ever purchased the parts (if available) to swap between calibers and shoot both.

It is sort of like a para cord bracelet, everybody wants one but nobody in history has ever used one for anything other than a prepper fashion statement.
yes and no...

i have a rob arms XCR-L bought it with a 6.8 bbl and ordered a 5.56 bbl and bolt from the manufacturer.... did a swap out once at the range after zeroing with 6.8, 5.56 pretty much held zero... i since switched back to 6.8 and kept it that way for a while, but its nice to know i have a spare bbl and bolt that will work... and its more efficient to carry around then another upper & optic...

definitely not for everyone, but i have confidence in my XCR in both calibers that i have for it
 
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