You will need to use H3 (5.4 oz) or heavier buffer as lighter H1 (3.8 oz)/H2 (4.6 oz) buffers will produce sharper/harsher recoil (Combined bolt/buffer weight needs to be around 19-22 oz ... FYI, PSA 9mm bolt weighs 14.7 oz) - https://www.thehighroad.org/index.p...back-recoil-impulse-9mm.924171/#post-12740825complete ... 9mm upper on a regular AR lower ... is there anything that has to be done to lower to get it to [accept] 9mm magazines?
Yes, Exomag does not require PMag shell donor and they are $22 each or $58 for 3 (Order "Ejector Version") - https://www.meanarms.com/products/detail/exomag-15-roundExomag for magazines not requiring adapter.
While it has always worked fine, I've considered a heavier buffer for a turnkey Colt 9. How can you determine the weight of the buffer?Colt and CMMG still use a 5.5 ounce buffer. 5.5 ounces is the minimum buffer weight.
Combined bolt/buffer weight should fall within 19-22 oz range using carbine length spring. If you go heavier, you may run into cycling issues and may "short-stroke" the bolt to not actuate last round bolt hold open (For match shooting to keep front sight flat without bolt/buffer slapping the back of buffer tube, this is actually desired by some shooters who don't need LRBHO ... See below for more discussion on short-stroking).considered a heavier buffer for a turnkey Colt 9. How can you determine the weight of the buffer?Colt and CMMG still use a 5.5 ounce buffer. 5.5 ounces is the minimum buffer weight. Most people run a 7.5 to 8.5 ounce buffer. I'm still running a 5.5 ounce buffer in my CMMG dedicated lower but am thinking about adding more weight to it.
How many rounds do you have on it? I am looking at those too. Only thing kinda holding me back is seeing lot of failures in low round counts.i did the 9mm ar15 2 ways:
1) 9mm glock lower, heavy buffer blowback upper. it worked fine. recoil was greater than a 223.
2) regular AR lower, mean arms endomag, and a cmmg radial delayed upper. uses a standard buffer, so converting from 223 to 9mm is and upper and mag sway only. The ejector is in the bolt face, so the plastic mean arms ejectors aren't needed. recoil was cut in half, and it was a lot quieter with a suppressor.
I immediately sold the blowback 9mm. I don't really care what system you use, radially delayed, roller delayed, whatever, there are a half dozen companies out there doing something now (cmmg, jp, mean arms, maxim to name a few) but using a delayed system is vastly superior to straight blowback.
So, I got an early one, and it killed the ejector spring pretty early on. Cmmg sent me a shorter stiffer spring that seems to be doing the trick. The original died at maybe 300 rounds. The 2nd is going strong at about 800 or so so far.How many rounds do you have on it? I am looking at those too. Only thing kinda holding me back is seeing lot of failures in low round counts.
Hmm, busy morning, I'll need a longer look at my Colt. IIRC, in addition to the buffer, there is a tungsten weight in the bolt itself. It has always run flawlessly (with the exception of one of the mag brands, that doesn't like HPs), and the recoil and 'cheek slap' has always been moderate.Combined bolt/buffer weight should fall within 19-22 oz range using carbine length spring. If you go heavier, you may run into cycling issues and may "short-stroke" the bolt to not actuate last round bolt hold open
If you reload, you can make small tweaks to the load to not over drive the bolt instead of going with heavier buffer weight.Hmm, busy morning, I'll need a longer look at my Colt. IIRC, in addition to the buffer, there is a tungsten weight in the bolt itself. It has always run flawlessly (with the exception of one of the mag brands, that doesn't like HPs), and the recoil and 'cheek slap' has always been moderate.
I'll have to check on bolt travel as well; don't want to lose the bolt stop boss on an SBR lower.
Again, thanks. My concern is more avoiding excess wear and tear on my SBR Colt, though, frankly, as little as I shoot it, it probably isn't an issue. I do have a ramped bolt, and a Geissele trigger; even in its 16" form, it never was common. It started life with A1 carry handle and sights; scored a flattop 10" Colt upper, and do like it with an optic.If you reload, you can make small tweaks to the load to not over drive the bolt instead of going with heavier buffer weight.
I use 5.4 oz H3 buffer weight with 14.7 oz PSA bolt but adjust my powder charges. Since I do not need last round bolt hold open, I adjust powder charge to "short stroke" the bolt to reduce bolt slap of buffer tube, depending on powder.
FYI, match/3-gun shooters prefer faster burning than W231/HP-38 powders for quicker seal with case neck/chamber wall and longer "dwell time" before bolt moves back and starts leaking gas for more consistent powder burn (Less soot on case) and greater accuracy - https://www.thehighroad.org/index.php?threads/9mm-target-load.927857/page-5#post-12846195