Test #2 - Results in Blue
Pre-test informational video:
https://www.youtube.com/watch?v=mBQVoO51hIA
Results video:
https://www.youtube.com/watch?v=sl66nGXBnlw
Goals:
- Since IMR 4227 consistently short stroked, find out if H335 will cycle reliably or if I need to test a third powder. Yep, it worked! Woohoo!
- Further refine the optimal velocity for this boolit, it should fall somewhere between 1992 and 2078 FPS. Did what I could for velocity estimates without proper load data, but the math seems to be confirming the window of best accuracy as slightly over 2000 FPS. Further testing required.
- Test my max COAL to see if it improves accuracy and/or cycling. Well I definitely didn't notice any detrimental effects from increasing COAL, so I'll stick with this 2.075" for now.
- Test a Dacron filler to see if it allows me to shoot a lighter load without compromising reliable cycling. Weirdly, Dacron made things worse for me. If any of you know why that might be, let me know.
- Observe all fouling to see how clean this powder runs, also watch for any signs of leading (none were present with IMR 4227). No evident of lead buildup except some "spray" around the inside of the flash suppressor, and powder fouling came out on the first dry patch, so this appears to be a pretty clean powder for me.
Test Groups (10 rounds each):
- 13.0 grains of IMR 4227 + Dacron filler. Estimated pressure is 21467 CUP, and estimated velocity is 2049 FPS.
- 17.5 grains of H335. No load data available, but best estimate is 1866 FPS.
- 18.0 grains of H335. No load data available, but best estimate is 1942 FPS.
- 18.5 grains of H335. No load data available, but best estimate is 2018 FPS.
- 19.0 grains of H335. No load data available, but best estimate is 2093 FPS.
- 19.5 grains of H335. No load data available, but best estimate is 2169 FPS.
- 17.5 grains of H335 + Dacron filler. No load data available, unclear how Dacron filler affects velocity.
- 18.0 grains of H335 + Dacron filler. No load data available, unclear how Dacron filler affects velocity.
- 18.5 grains of H335 + Dacron filler. No load data available, unclear how Dacron filler affects velocity.
- 19.0 grains of H335 + Dacron filler. No load data available, unclear how Dacron filler affects velocity.
- 19.5 grains of H335 + Dacron filler. No load data available, unclear how Dacron filler affects velocity.
Other Relevant Variables: Red text represents changes since last test.
- Projectiles: Boolits are 100% wheel weight alloy, water quenched, using the Lee .225 55 gr flat nose mold. If I absolutely can’t get 55gr boolits to both function and shoot accurately, I will either look into a heavier boolit (I’ve heard great things about the NOE 70gr) or consider changing my buffer spring out for a lighter one.
- Gas check: Aluminum gas checks are installed after casting using a Lee .225" push-through sizing die.
- Coating: Checked boolits are powder coated—baked at 400F for 20 minutes. Powder coat is Smoke's Clear. Coated boolits are then sized again back down to .225".
- Hardness: After PCing and sizing, boolits are allowed a minimum of 1 week to age harden before loading. Although I don't have a hardness test, I estimate the process of water quenching WW alloy, then semi-annealing during the PC process, then allowing to age-harden again is leaving me with a hardness somewhere in the range of 15-16 BHN.
- Brass: All I have is range pickup, mixed head stamps. All brass is decapped, lubed with Lanolin + 99% isopropyl alcohol, full-length sized using the Lee .223 pacesetter dies, and then wet tumbled with Dawn and Lemishine for two hours before being allowed to thoroughly air dry.
- Primers: All primers are CCI 400 small rifle primers (non-magnum).
- Loading Procedure: Necks are expanded prior to seating boolits using the Lee Universal Neck Expander die. Boolits are now seated to a near-max COAL of 2.075". After seating, a light factory crimp is applied to remove belled case mouths and allow the cartridges to chamber, but not enough to swage projectiles down smaller than .225".
- Shooting Procedure: For the sake of consistency, the same 20-round pmag is used for all testing. I am shooting off a bench using a Harris-style bipod. The bipod is rested on a sandbag rather than the hard bench top, and I am leaning into the bipod to load it for each shot. All targets for this test will be at 50 yards, as POI during Test #1 was not all that different than factory ammo. The longer range in Test #2 should allow me to more easily see how well different loads are grouping. Besides that, now that I’m confident I can get on paper at 50 yards, I can easily re-zero during this test, as my zero with jacketed ammo was set to 50/200 yards.
So now I just need to get back out and test this next powder. As usual, will post results when I have them.