I picked up a box of the Hdy 225 BTHP mainly for the 30-06, but figured I'd give them a go in the 308Win for R&D.....grin.
Here's a quick report of my findings today. The biggest surprise was that they were stable and accurate at 308 Win velocities, in a 1/12 twist bbl. It's a fairly long bullet at 1.585". I ran the data through the JBM stability calculator, and it calc'd stability in the "marginal" range.
Rifle used:
Rem 700 308 Varmint bbl, 1/12 twist, cut to 20.5"
McMillan HTG stock
Bushnell 3200 10X Mil/Mil
Load:
Hornady 225gr BTHP (moly'd)
Win brass
CCI 200 primer
RL-17 Powder, 48.0gr
MV: 2500 fps
OAL: 3.08" (.008" off lands)
I only loaded up 17 rounds for a quick test. The plan was to shoot two over the the chrono, five at 100 yds, five at 600 yds, and five at 1200 yds.
Two over the chrono clocked 2486, and 2492 fps at 10 yards. Call it 2500 fps MV for practical purposes, warmer temps, etc. Temp was about 30F, wind near calm. No signs of excess pressure. Primers looked normal, bolt lift normal.
105 yards: four of five went into .5". Based on the consistency of the four, I believe I pulled one shot that opened it up to 1".
590 yards: dialed 4.2 mils, and was right on the money on a melon sized rock. 5/5 hits.
1185 yards: Dialed 12.3 mils, three hits and two misses at 12 oclock on a 15" rock.
Hornady published BC for this bullet is .670. I read a couple reports here that it shoots closer to .710.
I did a traj table up using a BC of .700, 4500' el, std atmo. The predictions were right on at 590 yds, and a couple high hits at 1185 yds. Pretty close.
<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>
Gunsite altitude : 4500 ft.
Bullet : .308, 225gr, Hornady BTHP
Ballistic Coefficient(s) (G1): .700
Range Velo Time of Energy Path Deflection Total Sight correction Target
city flight to at crosswind drop for setting new lead
LOS of 10.0 Mph zero range 20 fps
-------------------------------------------------------------------------------------
·Yards fps s ft.lbs. in. in. MOA in. Mils MOA yds ·
-------------------------------------------------------------------------------------
| 0 2500 0.0000 3122 -1.8 0.0 ----- 0.0 ------ ----- 0.00
X 100 2394 0.1215 2862 0.0 0.3 0.26 2.8 0.0 0.00 0.81
| 200 2290 0.2496 2619 -4.2 1.7 0.81 11.7 +0.6 +2.04 1.66
| 400 2090 0.5250 2182 -33.4 7.9 1.89 50.2 +2.3 +8.00 3.50
| 600 1900 0.8230 1803 -93.6 18.1 2.89 119.6 +4.3 +14.91 5.49
| 800 1722 1.1571 1481 -193.9 34.7 4.14 229.1 +6.7 +23.16 7.71
| 1000 1557 1.5264 1211 -342.1 57.5 5.49 386.6 +9.5 +32.69 10.18
| 1200 1406 1.9287 988 -545.1 86.0 6.84 598.8 +12.6 +43.39 12.86
</pre></div></div>
Here's a quick report of my findings today. The biggest surprise was that they were stable and accurate at 308 Win velocities, in a 1/12 twist bbl. It's a fairly long bullet at 1.585". I ran the data through the JBM stability calculator, and it calc'd stability in the "marginal" range.
Rifle used:
Rem 700 308 Varmint bbl, 1/12 twist, cut to 20.5"
McMillan HTG stock
Bushnell 3200 10X Mil/Mil
Load:
Hornady 225gr BTHP (moly'd)
Win brass
CCI 200 primer
RL-17 Powder, 48.0gr
MV: 2500 fps
OAL: 3.08" (.008" off lands)
I only loaded up 17 rounds for a quick test. The plan was to shoot two over the the chrono, five at 100 yds, five at 600 yds, and five at 1200 yds.
Two over the chrono clocked 2486, and 2492 fps at 10 yards. Call it 2500 fps MV for practical purposes, warmer temps, etc. Temp was about 30F, wind near calm. No signs of excess pressure. Primers looked normal, bolt lift normal.
105 yards: four of five went into .5". Based on the consistency of the four, I believe I pulled one shot that opened it up to 1".
590 yards: dialed 4.2 mils, and was right on the money on a melon sized rock. 5/5 hits.
1185 yards: Dialed 12.3 mils, three hits and two misses at 12 oclock on a 15" rock.
Hornady published BC for this bullet is .670. I read a couple reports here that it shoots closer to .710.
I did a traj table up using a BC of .700, 4500' el, std atmo. The predictions were right on at 590 yds, and a couple high hits at 1185 yds. Pretty close.
<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>
Gunsite altitude : 4500 ft.
Bullet : .308, 225gr, Hornady BTHP
Ballistic Coefficient(s) (G1): .700
Range Velo Time of Energy Path Deflection Total Sight correction Target
city flight to at crosswind drop for setting new lead
LOS of 10.0 Mph zero range 20 fps
-------------------------------------------------------------------------------------
·Yards fps s ft.lbs. in. in. MOA in. Mils MOA yds ·
-------------------------------------------------------------------------------------
| 0 2500 0.0000 3122 -1.8 0.0 ----- 0.0 ------ ----- 0.00
X 100 2394 0.1215 2862 0.0 0.3 0.26 2.8 0.0 0.00 0.81
| 200 2290 0.2496 2619 -4.2 1.7 0.81 11.7 +0.6 +2.04 1.66
| 400 2090 0.5250 2182 -33.4 7.9 1.89 50.2 +2.3 +8.00 3.50
| 600 1900 0.8230 1803 -93.6 18.1 2.89 119.6 +4.3 +14.91 5.49
| 800 1722 1.1571 1481 -193.9 34.7 4.14 229.1 +6.7 +23.16 7.71
| 1000 1557 1.5264 1211 -342.1 57.5 5.49 386.6 +9.5 +32.69 10.18
| 1200 1406 1.9287 988 -545.1 86.0 6.84 598.8 +12.6 +43.39 12.86
</pre></div></div>
