Range Report – IMR 4227 behind 55g SPBT in my Oly AR 15.

[Hack]

Range Report – IMR 4227 behind 55g SPBT in my Oly AR 15.

I found the recipe for IMR 4227 on the Hodgdon’s website back in December. None on my manuals have 4227 in their tables. I looked online again today and it is gone. I think I know why, read on.

Back in December, Hodgdon’s recipe started with 16.0 g and ended with 17.0 g.

I really like the ease of metering IMR 4227. Much, much easier than IMR 4198 or 4064 – that’s one of the reasons for me trying IMR 4227.

I also liked the idea if using less powder. Figured it would make my pound of powder go farther.

So, I reloaded five recipes for IMR 4227 and none of them were satisfactory to me. All would make the Oly AR 15 eject the spent case, but most of the reloads would not drive the bolt back far enough to pick up the next round. I had to cycle the bolt by hand, using the charging handle.

Here’s the range report: I fired 10 rounds of each.

14.7 g of IMR 4227

Highest fps – 2402

Lowest fps – 2184

Average – 2329.86 (+/- 72.12 fps)

All ejected, bolt never went back far enough to pick up the next round.

15.0 g of IMR 4227

Highest fps – 2381

Lowest fps – 2252

Average – 2332.74 (+/- 48.25 fps)

All ejected, bolt never went back far enough to pick up the next round.

15.3 g of IMR 4227

Highest fps – 2495

Lowest fps – 2262

Average – 2372.44 (+/- 122.56 fps)

All ejected, bolt never went back far enough to pick up the next round.

15.7 g of IMR 4227

Highest fps – 2530

Lowest fps – 2331

Average – 2397.00 (+/- 133.00 fps)

All ejected, the bolt went back far enough to pick up the next round 2 times.

16.0 g of IMR 4227

Highest fps – 2560

Lowest fps – 2408

Average – 2501.00 (+/- 59.00 fps)

All ejected, the bolt went back far enough to pick up the next round 5 times.

I’m going to reload 16.5g and 17.0g to see if they will chamber the next round.

Do any of you guys have any experience with IMR 4227?

PS

While I was at it, I chronied 10 Remington Factory 55g loads, here’s the results

Highest fps – 2867

Lowest fps – 2724

Average – 2801.4 (+/-65.60 fps)

AR functioned flawlessly.

Later, I chronied 10 more of my 55g reloads, they were a recipe from my reloading manuals, 24.8 g of IMR 4064:

Highest fps – 2739

Lowest fps – 2597

Average – 2674.93 (+/-64.07 fps)

AR functioned flawlessly.

Hack

Edited March 15, 2009 by Hack