The following is most of the information for my conversion of my Bushmaster ACR from .223 Remington to .264 LBC-AR (aka 6.5 Grendel). If you think I left something technical out of this, you are correct and I did so for a reason. I know this rifle is very friendly to users looking to customize without a gunsmith but I think doing this kind of work entails more than a bit of danger if you are just ‘winging it’ without previous training and experience in Firearms Engineering (which I possess, especially with this rifle). I don’t want a job either, Firefighting allows me to do fun side stuff like this so why would I work for someone ever again. Also, I won’t coach anybody through a build like this because of possible liability issues. When I am satisfied that the parts are safe, I do intend to make the components available to everybody that believes in this platform as much as I do. Here are the tech specs:
Custom made 20” Stainless Heavy-Mid profile Fluted Barrel, .264 LBC-AR chamber
Standard ACR upper and bolt carrier group
Custom made ACR bolt for the .264 caliber (this would also fire a 7.62x39 round if the barrel was chambered for it)
Standard lower
Rock River Arms National Match Trigger group
Prototype ACR to PRS2 adapter
Magpul PRS2
C products 6.5 magazines(blue follower)
Hornady 6.5 Grendel 123 gr Amax Ammunition
Burris Optics Black Diamond 8-32x50mm Scope and Burris 30mm Signature Zee Rings
Mako Group Grip pod Bipod/Vertical Foregrip
This build has taken me about a year to assemble all the pieces with my finances the way they are and two kids(three if you count the wife). Some of the parts are irreplaceable right now so I won’t be thinking of selling any of them until I do a commercial sized run of parts. If I had to guess at the final price tag with all the engineering work, parts, and testing I would figure that I have easily quadrupled the msrp of this rifle. That’s pretty typical for this kind of work though.
I should also note that I have had advanced military training so I shoot well but I think this rifle could shoot even better in the hands of a shooter that is trained and experienced in the art of long range shooting. I can read trace, mirage and wind but I don’t make my living at it.
I have omitted the name of the barrel manufacturer because I would not recommend them to anyone(maybe someone I don’t like) and I won’t use that manufacturer for any build in the future. If you figure out who did the barrel and want to use them, good luck and you will be using a couple of calendars to measure how long it’s going to take to get a barrel out of them. I got ‘hooked up’ because I was ‘in the industry’ and it took 8 months and they doubled the quoted price at the end. The bolt was fabricated by a local machinist that is very talented and he will be the one making future bolts for me. Also, thank you to Keith at Rocky Mountain Shooters for getting some clean up gunsmithing done for me very quickly at a great price. If you are in the area I recommend him. I had no problems with the C Products magazines but they aren’t in business any longer so I consider them good enough for this build. I don’t know that I would trust my life to them yet. The only malfunctions I had with this gun were when I was working with the gas system to get the rifle gas port tuned to the action. I attribute those malfunctions to a non-tuned gas system rather than the rifle or the magazine. The grip pod was fun and may have some applicability to this platform. I wish it was a bit smaller and lighter because it is pretty huge in real life. The trigger group from RRA is good enough for me. I noticed the difference switching from the OEM trigger but I don’t think I would be good enough to tell the difference in the Geissele trigger compared to the RRA, although I would love to try it out if I had the cash for curiosity. The RRA trigger is the value buy for me on this build. Thanks to Hornady, if it wasn’t for them I would be buying Wolf. The rounds have been great every time out of the pipe. Thanks to the Burris Guys for the hookup on the Black Diamond and rings. I used to work there and I know how good that scope is from an engineering standpoint. It held up its end on this build and was more than cost effective considering the shooter. Finally a big thanks to Magpul for letting me work on the Masada in the prototype phases which gave me intimate knowledge of this platform and a solid knowledge base to attempt this endeavor. Even though I don’t work there anymore I still consider the guys and gals over there to be good friends and more than helpful when I needed some help.
I figure the rifle shoots just under 1 MOA or better which is ok for a precision gas gun and a moderately skilled precision shooter. The weight comes in at 12.4 lbs with an empty magazine according to the bathroom scale. The recoil is very comfortable and the bang is quiet enough that some people/cows over the next rise didn’t even know I was shooting until they came over. I did not notice any change in POI shift by removing the barrel and replacing it but I don’t plan to do that very often for this prototype setup because it may turn up in the longer range shots. The barrel tip is threaded because I would like to fabricate my own suppressor for this system in the future (BATF, don’t worry I know the rules for that sort of thing). In the pics to follow, all the distances are in yards even though a couple of the targets have meter designations (old habit). This rifle will shoot all day long at 600. Especially since I can turn up the magnification to 32x and the groups go to very good (I used a controversial target so I am not positing that it). The other ranges require the scope to be at 14x for the reticle to match the ballistics calculator I was using. Counting all the rounds I used for tuning the gas system, sight in, and then range days, I have about 150 rounds down the pipe. I haven’t seen any major signs of wear and tear or damage but I plan to inspect the bolt with some industry standard inspection practices to make sure there is nothing I am missing on this one.
All in all I am very happy with this build and I am also happy that I can put it down just in time for archery season. Maybe after I fill the freezer with elk and I get the 6.5 bolts done I will work on a 7.62x39 setup(I might use Wolf ammo then) and then who knows what I will add to this platform. I will post again about this stuff when I have the company formed and am ready to take preorders for the first run of bolts. Thanks for taking the time to read this.
Mike
Custom made 20” Stainless Heavy-Mid profile Fluted Barrel, .264 LBC-AR chamber
Standard ACR upper and bolt carrier group
Custom made ACR bolt for the .264 caliber (this would also fire a 7.62x39 round if the barrel was chambered for it)
Standard lower
Rock River Arms National Match Trigger group
Prototype ACR to PRS2 adapter
Magpul PRS2
C products 6.5 magazines(blue follower)
Hornady 6.5 Grendel 123 gr Amax Ammunition
Burris Optics Black Diamond 8-32x50mm Scope and Burris 30mm Signature Zee Rings
Mako Group Grip pod Bipod/Vertical Foregrip
This build has taken me about a year to assemble all the pieces with my finances the way they are and two kids(three if you count the wife). Some of the parts are irreplaceable right now so I won’t be thinking of selling any of them until I do a commercial sized run of parts. If I had to guess at the final price tag with all the engineering work, parts, and testing I would figure that I have easily quadrupled the msrp of this rifle. That’s pretty typical for this kind of work though.
I should also note that I have had advanced military training so I shoot well but I think this rifle could shoot even better in the hands of a shooter that is trained and experienced in the art of long range shooting. I can read trace, mirage and wind but I don’t make my living at it.
I have omitted the name of the barrel manufacturer because I would not recommend them to anyone(maybe someone I don’t like) and I won’t use that manufacturer for any build in the future. If you figure out who did the barrel and want to use them, good luck and you will be using a couple of calendars to measure how long it’s going to take to get a barrel out of them. I got ‘hooked up’ because I was ‘in the industry’ and it took 8 months and they doubled the quoted price at the end. The bolt was fabricated by a local machinist that is very talented and he will be the one making future bolts for me. Also, thank you to Keith at Rocky Mountain Shooters for getting some clean up gunsmithing done for me very quickly at a great price. If you are in the area I recommend him. I had no problems with the C Products magazines but they aren’t in business any longer so I consider them good enough for this build. I don’t know that I would trust my life to them yet. The only malfunctions I had with this gun were when I was working with the gas system to get the rifle gas port tuned to the action. I attribute those malfunctions to a non-tuned gas system rather than the rifle or the magazine. The grip pod was fun and may have some applicability to this platform. I wish it was a bit smaller and lighter because it is pretty huge in real life. The trigger group from RRA is good enough for me. I noticed the difference switching from the OEM trigger but I don’t think I would be good enough to tell the difference in the Geissele trigger compared to the RRA, although I would love to try it out if I had the cash for curiosity. The RRA trigger is the value buy for me on this build. Thanks to Hornady, if it wasn’t for them I would be buying Wolf. The rounds have been great every time out of the pipe. Thanks to the Burris Guys for the hookup on the Black Diamond and rings. I used to work there and I know how good that scope is from an engineering standpoint. It held up its end on this build and was more than cost effective considering the shooter. Finally a big thanks to Magpul for letting me work on the Masada in the prototype phases which gave me intimate knowledge of this platform and a solid knowledge base to attempt this endeavor. Even though I don’t work there anymore I still consider the guys and gals over there to be good friends and more than helpful when I needed some help.
I figure the rifle shoots just under 1 MOA or better which is ok for a precision gas gun and a moderately skilled precision shooter. The weight comes in at 12.4 lbs with an empty magazine according to the bathroom scale. The recoil is very comfortable and the bang is quiet enough that some people/cows over the next rise didn’t even know I was shooting until they came over. I did not notice any change in POI shift by removing the barrel and replacing it but I don’t plan to do that very often for this prototype setup because it may turn up in the longer range shots. The barrel tip is threaded because I would like to fabricate my own suppressor for this system in the future (BATF, don’t worry I know the rules for that sort of thing). In the pics to follow, all the distances are in yards even though a couple of the targets have meter designations (old habit). This rifle will shoot all day long at 600. Especially since I can turn up the magnification to 32x and the groups go to very good (I used a controversial target so I am not positing that it). The other ranges require the scope to be at 14x for the reticle to match the ballistics calculator I was using. Counting all the rounds I used for tuning the gas system, sight in, and then range days, I have about 150 rounds down the pipe. I haven’t seen any major signs of wear and tear or damage but I plan to inspect the bolt with some industry standard inspection practices to make sure there is nothing I am missing on this one.
All in all I am very happy with this build and I am also happy that I can put it down just in time for archery season. Maybe after I fill the freezer with elk and I get the 6.5 bolts done I will work on a 7.62x39 setup(I might use Wolf ammo then) and then who knows what I will add to this platform. I will post again about this stuff when I have the company formed and am ready to take preorders for the first run of bolts. Thanks for taking the time to read this.
Mike