Load development: one load, different barrel lengths

[BravoGolf59]

I tried searching for this with no luck.

If you wanted to develop a given load to work in multiple ARs with different barrel lengths, but same twist, which barrel length would you use for initial development?

I expect the responses will be something like "whichever rifle you expect to shoot the load in the most". But, let's suppose it is equal amounts between all lengths. Does it make a difference?

Thanks in advance!

[markm]

We always chrono off a 20 inch barrel for complete comparability.

FWIW... our most successful multi gun load is 21.6 gr H322, 77 gr SMK, and WOLF SRM primer. Just shoots great in everything. SBRs, Bolt gun, etc.

[BravoGolf59]

Markm, thanks for your response. I did not consider comparability; good idea! Thanks for your load tip, I will store that one away for the future.

[markm]

Markm, thanks for your response. I did not consider comparability; good idea! Thanks for your load tip, I will store that one away for the future.

Yeah.. it gets too confusing otherwise.. This velocity out of a 12.5", that one out of a 14.5" etc.

[JimmyB62]

I think you also have to decide if your emphasis is on velocity or accuracy (or something else). A very accurate load from the longer barrel may be very slow in the shorter barrels. If you're more concerned about longer range accuracy it may not matter as much. If you're trying to develop a close range combat load then velocity might be more important. Some powders work better out of shorter barrels and some are clearly better when chasing precision loads.

It may sound simple, but know what your priorities are before you start developing.

[BravoGolf59]

JimmyB, that is somewhat the train of thought I was on, which lead to this topic question. Thanks for verifying that I was not missing something.

MarkM, I wanted to ask on your "all around" 77 SMK load, are you using cannelured, or non? In a bolt gun, what was the twist?

Thanks for the responses! :cool:

[markm]

MarkM, I wanted to ask on your "all around" 77 SMK load, are you using cannelured, or non? In a bolt gun, what was the twist?


Mostly non-cannalured... although I've loaded some with. The bolt gun is a 5R rem 700 with nominal 1/9 twist... although I think it may be faster... because it'll stabilize even 80 grainers out to 1000 yards.

[WC 2-3]

Mostly non-cannalured... although I've loaded some with. The bolt gun is a 5R rem 700 with nominal 1/9 twist... although I think it may be faster... because it'll stabilize even 80 grainers out to 1000 yards.

Seems like barrel length might play a role in slower twist rates being able to stabilize heavies. A Friend has two 24" Colts 1/9 that shoot the heavies great.

[BravoGolf59]

Thanks!

[T2C]

We always chrono off a 20 inch barrel for complete comparability.

FWIW... our most successful multi gun load is 21.6 gr H322, 77 gr SMK, and WOLF SRM primer. Just shoots great in everything. SBRs, Bolt gun, etc.

This is good to know. What is the muzzle velocity, extreme spread and standard deviation out of a 20" barrel?

[markm]

This is good to know. What is the muzzle velocity, extreme spread and standard deviation out of a 20" barrel?

I'll have to get back to you. The book is at home.... and I went ape shit chronoing everything when I got my magnetospeed last month. :p

[ICANHITHIMMAN]

I tried searching for this with no luck.

If you wanted to develop a given load to work in multiple ARs with different barrel lengths, but same twist, which barrel length would you use for initial development?

I expect the responses will be something like "whichever rifle you expect to shoot the load in the most". But, let's suppose it is equal amounts between all lengths. Does it make a difference?

Thanks in advance!

In my opinion there are just to many variables to your question, . I guess I would start with which ever rifle has the most propensity for consistency and once the load is GTG there move to another platform and check your results, I see you doing a lot of back and forth, so I would choose the best group average with one load from all rifles.

[shootist~]

...which barrel length would you use for initial development?

Three barrels and two loads in my case: 18" SPR Barrel , 16" CL, & 14.5" CL.

77 gr loads were worked up in the SPR 18" barrel. Follow up testing in the other two with needed adjustments to any standard zeros noted.

I only have one other standard reload - a 55 gr "practice load". It was just put together based on a popular standard powder charge - no serious workup involved other than to chronograph and verify it's acceptable for the intended uses in all three rifles. It's for CQ drills and running out to ~300 Meters.

[BravoGolf59]

"the most propensity for consistency" - that's a good thought!

Thanks for all the great responses, and Happy 4th!!! :cool: