AR vrs RAP 85 grain Sierras

[Jpereira94]

Did some testing today with my 18" Ar and RAP. I loaded two 10 round ladders using 28.2 to 30.0 grains of benchmark. The results where not what i expected! The 18" AR had faster fps.

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[Lemonaid]

Interesting. In general, does the Ar beat the Rap for velocity or is this an anomaly?

[Jpereira94]

First time trying this. Definitely going to try more loads out!

[grayfox]

Overall the 18 maybe slower, maybe ~same, to me, with a definite lower bottom MV in its set. The 60 or so delta at the top, for 2 1-shot strings, I would not put a lot of weight into. I would wait on that conclusion until I did some load-set MV testing with 4-5 rounds per load charge, and some usable MVs out of that.
Also, Ruger could have a rougher interior to its barrel...

[JTPinTX]

Interesting. With the 85 Sierra HP and 30 grains of Benchmark, I am only getting 2675 out of my 16" AR with a Monster barrel. Very accurate load for me though, and has been putting pigs down good.

[DCC83501]

Benchmark and 85 Gr Sierra HP don't get along with my PF 16" Lilja. However, 29 Grains of AA2200 have them doing 2810 fps and grouping better than my pay grade! One hole five shot groups at 100 yards pretty consistently, or easily under MOA. I did load some at 29.3 gr and 29.6 gr. but only shot the 29.3 as I seemed to be getting ejector swipes. Have since declawed my extractor and rounded edges on ejector and may try those again. 29.3 grain was right at 2840 fps.

[Jpereira94]

Overall the 18 maybe slower, maybe ~same, to me, with a definite lower bottom MV in its set. The 60 or so delta at the top, for 2 1-shot strings, I would not put a lot of weight into. I would wait on that conclusion until I did some load-set MV testing with 4-5 rounds per load charge, and some usable MVs out of that.
Also, Ruger could have a rougher interior to its barrel...

I have been trying out the satterlee method to see if I like it. Also I was thinking that the ar has a higher round count then the rap so that might be a big factor.