In this case, I'm going to say that 5 shots of each isn't a very statistically valid sample size, and (IIRC) the difference that Federal shows for the non +P load vs the +P load is 50fps from a pistol length test barrel ... I'd feel pretty good about guessing that Federal uses the same powder in both loads, and just a smidge more in the +P load. I don't think more powder could reduce velocity... but I'm not a ballistics expert. That said, with 147gr 9mm loads, I do think it's possible to run out of powder/gasses/expansion to generate more velocity after a certain barrel length. And I suppose at some length, you'd be slowing the bullet down before it exits the muzzle. You can find some data about this stuff on the "ballistics by the inch" webpage.
I've been looking at building a Glock mag AR in 9mm, and I'll probably go with a ~10-12" barrel to get the most out of my preferred 147gr loads, but still be long enough to see some velocity gain with lighter 115-124gr bullets. I think that length is the "sweet spot" for 9mm carbines/SMGs.
A slower burning powder works better in a longer barrel.
US Navy Veteran
1961-1965
Does anyone have professional test data yet on the revised 147gr P9HST2 & P9HST4 loads? Really wondering how they're doing through 4LD and if reports of flashiness and lower velocities are holding with recent product.
Don't know if you are still working with it or not but here's what I found for my 9mm AR carbine for USPSA PCC division. We are loading for a minimum power factor of 125 (bullet weight * velocity / 1000). I load with very fast powders and for this one I was using WST and faster yet, Alliant e3 which is fast like N310 and Red Dot. I was getting around 142PF with as light of a charge as I was comfortable with running in the 16" barrel. I found that if I needed to game it lower I was going to have to lighten up the bullet weight. I'm relatively sure that I'm running faster powders than the non-canister powders the factory use but who knows?
In the FWIW category, in an AR pistol with a 7" barrel, Win Ranger T 127+P+ made major right at 165 PF (1307 FPS). I expected it to be a bit faster.
Made the universal switch to 147-grain standard-pressure HST in my 9mm firearms today with a big order from SGAmmo.
I have been using Speer Gold Dot 124 +P for 5-6 years and still trust it entirely (and have a few boxes stashed for ammo droughts) but HST is a few bucks cheaper per box and offers equivalent performance. Provided all my guns run it to my satisfaction that'll be my new carry ammo.
I've sold 9 guns this year, but my incoming new M&P2.0 Compact 9mm, holster, and HST pallet will be a happy exception to the rule and I am looking forward to some range time.
Last edited by LockedBreech; 05-28-2018 at 06:40 PM.
State Government Attorney | Beretta, Glock, CZ & S&W Fan
Bill I'm late to the party on this one, not sure if you'd made any final decisions.
For a 16" carbine, the lighter bullets tend to work a wee bit better in terms of speed. I actually really like 9BP-LE out of a 9mm carbine. The 115-grain bullets at +P+ push out the end of 16" barrels at .357 mag velocities (~1400 fps). The problem is - they tend to fragment when they hit anything hard (wood, bone, laminated windshield glass, metal) at that speed. I prefer the fragmentation on hard surfaces for inside the house work.
For outside the house work, 124-grain HSTs are my preference.
ETA: Like others, for me over the last four years HST has become my carry ammo of choice in 9mm and .45. Whatever is available is what I will use, with a preference for 147-grain standard pressure, but I won't hesitate for any of the +P/SP varieties in 124-147 grain weight category.
Last edited by RevolverRob; 06-01-2018 at 04:09 PM.
@DocGKR
Thanks as always for your expertise and advice.
I am a low volume armed civilian, and it is time to order some more defensive ammo.
Since this thread was started, has Federal HST 147 continued to perform as expected in "real world" situations?
Thank you again.
Rich