[Gary Smith]

@kluthe: If you go to the Hodgdon Reloading Data website, you’ll find AutoComp loads for 124 gr Berry’s and XTPs. The former OAL is given at 1.150″ and for the latter at 1.060″, and charge weights ranging from 4.5 to 5.4 gr. That window is narrow enough to keep folks out of trouble.

As for the OP, chronographs vary from user to user and brand to brand, and atmospheric conditions affecting air density (like altitude, temperature and even humidity to some degree) will alter velocity measurements. As an example, I have yet to see a Lab Radar record a lower velocity for my 9mm and .45 ACP loads than my dated Chrony, which is a conservatism I appreciate for major matches. However, this powder was designed around race guns using compensators (hence the name), so it wouldn’t be my first choice for general purpose target shooting or competing in divisions where comps are not allowed.

[Gary Smith]

The RMR jacketed bullets have proved more accurate for me than the plated bullets you mentioned. FWIW, you might try coated bullets as a less expensive alternative – look at offerings from Bayou Bullets, SNS Casting, and Blue Bullets.

[Gary Smith]

The Wilson case gages are great tools, but when I run into troubles or I’m loading for a major match, the barrel from the gun I’ll be using becomes my case gage. ALMOST foolproof! My 9mm 1911 isn’t real fussy, but my CZ Shadow 2 is.

Understand that putting a hollow point or a flat nose on a bullet changes its mass distribution. I find it useful to measure the length of the bullets I’m using as part of my loading strategy. E.g., a 124 HP will be longer than a 124 RN, so if you don’t change the seating depth (thus OAL), the HP will be seated deeper into the case and will normally result in higher pressures and velocities.

[Gary Smith]

Using RMR 124 RN FMJ bullets in a 5″ Colt Gold Cup Trophy

No loads listed showed any primer flattening or other signs of excessive pressures.

Unique – mixed brass, Win primers, 1.270 OAL
5.6 gr – 1176 fps
5.9 – 1215
6.2 – 1244

Accurate #5 – mixed brass, Win primers, 1.270 OAL
7.0 gr – 1088 fps
7.6 – 1130 (most accurate)
7.8 – 1212
7.9 – 1225
8.0 – 1258

Accurate #7 – Starline brass, Win primers, 1.260 OAL
9.1 gr – 1293 fps
9.3 – 1296
9.5 – 1356
9.8 – 1374
10.0 – 1397

[Gary Smith]

Bullet: RMR 124gr RN-FMJ
Primer: Winchester SPP
Case: Mixed
Charge wt: 4.0 gr
Powder: Titegroup
COAL: 1.150″
Springfield Range Officer (5″ bbl) – 1088 ft/sec
Ambient Temp. 63F

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