The 300BLK was designed to function in an AR with no modifications other than a barrel swap which means standard carbine spring and buffer weight. I'm not saying it won't work with an H2 but you may not have the same reliability if you want to shoot supersonic and subsonic loads. The only way to know is to try it out but you may want to pick up a standard carbine weight buffer before changing anything else if you have reliability issues.
300BLK Build Begins - And Ends
- Thread starter BillD
- Start date
The 300BLK was designed to function in an AR with no modifications other than a barrel swap which means standard carbine spring and buffer weight. I'm not saying it won't work with an H2 but you may not have the same reliability if you want to shoot supersonic and subsonic loads. The only way to know is to try it out but you may want to pick up a standard carbine weight buffer before changing anything else if you have reliability issues.
I opted to get the H2 for my gun initially just because that's what CC runs in their guns and although I put it together from parts, they're all CC parts. But when putting my upper together I read in a few places that AAC recommends running H2 buffers so I figure I'll go with it and address an issue should it arise. So far it's been okay with American Eagle 150gr.
Good to hear, think I'll pick up some Campro .308 too for general plinking loads.
Yes, I have a 6" metal chop saw I bought just for making 300BLK brass. I cut the 223 brass at the shoulder, then I debur the mouth, then sizing die, then trim to length then inside/outside chamfer, then load. I use Remington 223 headstamp brass exclusively and i have some that is on it's 5th loading, never annealed and have had no problems with my brass.
Cool. I need to make or order a jig for cutting them down, but I got impatient so I cut some off with my dremel and a cutting wheel. Deburred them and then ran them through the sizing die and cleaned them. I still need to trim it, but my trimmer is on order. I'm sure some are cut too short, but I think most of them will be okay and as long as I'm the only guy at the range who picks up .223/5.56 brass I'm prepared to sacrifice a few.
If you're ever in the Ottawa area let me know, I owe you a beer.
Are these the 110gr V-Max bullets your data sheet is referring to? If they are I'm probably going to pick up a box.
http://www.theammosource.com/index.php?main_page=product_info&cPath=15_19_169&products_id=3373
Also, am I reading the chart correctly that Hornady 208 A-max loaded with H110 is supersonic rather than sub?
http://www.theammosource.com/index.php?main_page=product_info&cPath=15_19_169&products_id=3373
Also, am I reading the chart correctly that Hornady 208 A-max loaded with H110 is supersonic rather than sub?
Last edited:
I'm not sure, I use 110 V-max over 19.4gr of H110, I'd suggest you start around 18.8-19gr and work up in small increments until you find an accurate load or see pressure signs.
Don't use H110 for 208gr projectiles, from what I remember from my early testing they didn't cycle my rifle (first 300BLK was a PWS 10 inch piston driven AR). If you want 208gr subsonic and for it to cycle your action you'll need Accurate A1680 and if I recall correctly around 12.4gr is the lowest you can go before it won't cycle any more and it's right around 1050-1100fps depending on the barrel (I've had 10, 12, and 18.6 inch semi's in 300BLK).
My basic reloading guide to powder selection is that I use H110 for projectiles up to 130gr supersonic, Lil'Gun for 130-165gr supersonic, A1680 for 150 up to 208 supersonic and for 208gr subsonic. I have some loads made with IMR4227 but haven't tested any yet so can't really comment on how it performs. Getting your semi to cycle reliably requires using the right powder for your projectile selected. Not everything published as load data was worked up in a semi auto so not all published loads will cycle nicely.
Strangely I've been having more fun loading for my 16 inch Remington AAC-SD in 300BLK, I've got a 150gr FMJ load with Trailboss that is a lot of fun, subsonic and pretty accurate.
Thanks for the invite, same on this end, if you or anyone else is around Edmonton and wants to shoot I have land north of the city and shoot regularly in my yard. I have a 100yd range 10ft out the back door of my shop. Good opportunity to try out anything in my collection (as far as I know I am one of two people in Canada that has built a non restricted 300BLK conversion for the ACR)
Last edited:
I hear ya. Personally I can't wait to see your all done and running.
I have a question for the reloaders. On a bit of a whim I bought a bag of once fired 300blk brass from Western Metal. When resizing I, well, I got a little carried away with the lube which seems to have resulted in some dents on the shoulders of some of the cases. From what I have read those cases should still be safe to use and will fire form to the chamber when fired. Do you (BillD or cr5) have any input on this?
I have a question for the reloaders. On a bit of a whim I bought a bag of once fired 300blk brass from Western Metal. When resizing I, well, I got a little carried away with the lube which seems to have resulted in some dents on the shoulders of some of the cases. From what I have read those cases should still be safe to use and will fire form to the chamber when fired. Do you (BillD or cr5) have any input on this?
Shoot them, the dents will pop out.
What are you using for lube? I use what I think is Hornady case lube, comes in a little white tub with red lettering on it. I've used it for thousands of cases and still have more than half left. It's like a wax and I just wipe my finger in it then rub the brass around in my fingers on the way to the sizing die, it never leaves dents.
Full length size then check case length and trim if required. Sizing them will change the length so I measure them after they're cleaned and sized.
What are you using for lube? I use what I think is Hornady case lube, comes in a little white tub with red lettering on it. I've used it for thousands of cases and still have more than half left. It's like a wax and I just wipe my finger in it then rub the brass around in my fingers on the way to the sizing die, it never leaves dents.
Full length size then check case length and trim if required. Sizing them will change the length so I measure them after they're cleaned and sized.
I'm using the Lyman spray lube. It wasn't the lives fault though. I've already resized a whole bunch of cases with no issues. I had the brilliant idea to apply a little to the inside of the die and I'm pretty certain that's what caused the issue. Like I said operator error.
Dang! Who bought it all?! lol
