16" .308 loads

[mark5pt56]

So, I'm waiting on my 16" CA MPR to arrive from EO and have some thoughts and questions on powder and bullet choice. First off, I have a 6.5CM, so for what it's worth, got that out of the way.

For the most part, this is intended to be a hunter and precision. Most of it being under 600 for precision and well under that for hunting, but may press it further for the heck of it.
It would be nice to hunt (deer) with the same bullet, so thoughts on the Hornady ELDX or the older BTHP?

I have 400 168 SMK's left over and will use those first with 4064. I'm considering the 175 SMK or TMK with 4064. Leaning on the SMK as I understand may be easier to work a load vs the TMK? Also maybe later try the 185 Berger Jugs and 2000MR.

Will have to be mag length and right now have a decent supply of BH match brass. Other than 4064, any other powder suggestion for temp stability and good speed with short barrels? A buddy suggested IMR4895 as it may work well in shorter barrels.

Appreciate any info and suggestion.

Mark

 

[bruddah]

It's just me, but that seems like an extremely short barrel for 308

 

[MtnCreek]

Hard to beat H4895 178amax in a 20" for general purpose. I guess that's eld-m now. I would expect it to do pretty good in 16".

 

[mark5pt56]

Hard to beat H4895 178amax in a 20" for general purpose. I guess that's eld-m now. I would expect it to do pretty good in 16".

Yeah, have some H4895 and 4064, might pick up some 178X' to try out.

 

[MarkCO]

That is a short barrel for the rounds you look to be assembling. In my 16" .308, I get the best results with lighter bullets and faster powders. Feel free to experiment, but I ignored the same advice at first. Not only will you get better ballistics, but your gas rings and bolt will thank you as well.

 

[MtnCreek]

I just realized this is an autoloader.

If you want a handfull of 178 amax to test over a chrony, shoot me a pm with mailing info and I'll get some headed your way. Old bullet, but should be sufficient to see if you're able to push a 178 class bullet fast enough.

 

[mark5pt56]

Christensen Arms MPR, bolt gun. Will PM later, headed to work, I mean the range-hehe

 

[Wyfox]

I run 168gr Nosler CC with CFE223 in my 16.5" 308. Velocity is 2460 fps.
After I shoot all the 168's I may switch to the Scenar 155's for more velocity.

 

[mark5pt56]

As I understand the heavier bullets perform better across the board in various barrel lengths? That's why I was going for the heavier ones to start. Been doing some reading and not sure about powders though. I did read AR comp and cfe223 do well, I do have cfe223 on hand.

I ran some JBM numbers and used projected velocity based in reading and what my 18" Tikka does with 168 AMAX (2525) Have to double check the powder, either 4064 or H4895.

Anyhow SMK 155/168/175 and 178 ELDX, 2-1k and 60 degrees, 0 DA 10 twist barrel and used the G1 and published length's

Appears that the heaviers-175-178 do better.


155 @2525 168 @2475 175 @2450 178#2450

DROP/WIND
200 .6/.5 .6/.5 .6/.5 .6/.4
300 1.5/.8 1.5/.8 1.5/.7 1.5/.7
400 2.5/1.1 2.6/1.1 2.6/1 2.6/.9
500 3.8/1.4 3.9/1.5 3.9/1.3 3.8/1.2
600 5.2/1.8 5.5/1.9 5.3/1.6 5.1/1.5
700 6.9/2.2 7.2/2.3 6.9/2 6.7/1.8
800 8.8/2.7 9.2/2.8 8.8/2.4 8.4/2.2
900 11.1/3.1 11.6/3.3 10.9/2.8 10.4/2.6
1000 13.6/3.6 14.3/3.7 13.2/3.2 12.7/3

 

[mark5pt56]

Just to add,for under 500, it doesn't appear to matter. My hope/plan is the 178 eldx to work accuracy wise and I'm in. Same bullet, meat or paper. Unless there's a 150-165 class bullet that would be better? for both roles. Mag length and not jump sensitive if possible. An honest .75, 1moa max on a bad day

 

[Silverjay]

Look at 8208XBR und4 a 175. Good velocity for the barrel length and meters well.

 

[Wyfox]

The 155 scenar has a pretty high BC for it's weight class.

 

[briang7511]

I have a 18in 308 and run 46gr of varget with a 155 amax. i have also used the 155 sierras with Rl15.

 

[81sfo]

Stick with the heavies! 168 Amax would be the lightest bullet choice , imr xbr 8208 43 gns in BH brass ,Lapua or Winchester . Do not try that load in Lake city or Fed brass . 175 ,178s Rock in my short barrels, again imr xbr , but mostly run power pro 2000mr for a boost in velocity. You can't get the 155s fast enough to be worth it in my opinion.

 

[mark5pt56]

Mtncreek has some 178 AMAX' headed my way. Think I might add the 8208 to the try list that gives me 3, 4064/cfe223/8208. That'll let me pressure test those and give me a guide for further test. While accuracy is first, well safety but that's a given, my goal is a least 2450 with a safe and accurate load. I'll take more if it shakes out though.

 

[Niles Coyote]

I run 168gr Nosler CC with CFE223 in my 16.5" 308. Velocity is 2460 fps.
After I shoot all the 168's I may switch to the Scenar 155's for more velocity.

Hornady's 168 Eld now significantly bests the bc of the scenar and the old school 175 smk. Sierra's 168 TMK isn't far behind... if you can get it the group. My auto shuckers don't care for that one though.

 

[mark5pt56]

Stick with the heavies! 168 Amax would be the lightest bullet choice , imr xbr 8208 43 gns in BH brass ,Lapua or Winchester . Do not try that load in Lake city or Fed brass . 175 ,178s Rock in my short barrels, again imr xbr , but mostly run power pro 2000mr for a boost in velocity. You can't get the 155s fast enough to be worth it in my opinion.

Wow! Hornady list 41 as max. Guess you worked it up of course. They do seem a bit conservative though.

 

[81sfo]

I use Hodgdon manual it calls for 43 xbr with a 168 and it works amazing !

 

[mark5pt56]

I use Hodgdon manual it calls for 43 xbr with a 168 and it works amazing !

oh yeah, 168, I was thinking 178

 

[81sfo]

178 i used Hodgdon manual aswell 42.5 xbr in my Obr 16" semi auto Winchester brass , 2425 fps good out to 1100 yds if no wind was present. Hehe

 

[mark5pt56]

Okie, thank you, will look at that.

 

[samnev]

I used 4895 with 168 SMK's for many years while competing in club matches. When the 308 AR's came on the scene used the same load with excellent results in my LMT MWS, DPMS SASS and Armalite AR10. Now shoot a similar load in my AIAW and TRG 22.

 

[newguy2k3v2]

You can get 2600 or a little better with a 175/178 bullet and a stiff load of 2000mr. Es/SD are always good but velocity does fluctuate some with temp compared to Varget etc.

 

[Beneviolence]

My issue with poly-tipped, high BC, heavy 308 bullets is getting enough powder under the bullet and meeting mag length COAL, especially with 4064. My experience pushed me away from TMK/ELD-X/M's and more towards SMK/RDF's.

 

[mark5pt56]

I found this that I posted in 2014 and using a 22" Bartlein.

I forgot about it and found it searching about on AR15. As I wait for my rifle, I will try to locate some 2000MR.

For my FN custom (22" Bartlein) ​

43 IMR4064/175SMK 2.8/FC case/FGMM ​

primer​

(2675 FPS) ​

43 IMR4064 /178 ​

Hornady​

BTHP/2.840 (2683 FPS) ​

47 2000MR/178 H BTHP/2.840 (2775 FPS) ​

47 2000MR/185 Berger ​

Juggernaut​

2.850 (2700 FPS) ​

 

[eveyoz]

How about twist rates? Im looking at using a spare 1 in 12 heavy palma for a 16" barrel for my AI, Im not sure it will stabilise well with that twist rate. I mostly shoot 168gr projectiles using varget in my 20" and 24" 308 rifles/barrels.

 

[Doom]

Old thread but 12 twist and 168 SMK is fine at 2400 fps, Sg is 1.528 at 20F, sea level.

 

[JR1200W3]

LOL, dude dug up a 7 year old thread about load data to ask about barrel twist stability that could've been answered on Bergers free stability calculator

 

[eveyoz]

LOL, dude dug up a 7 year old thread about load data to ask about barrel twist stability that could've been answered on Bergers free stability calculator

Wow, I’ll check it out and enter 16” barrel length. Thanks

 

[JR1200W3]

Wow, I’ll check it out and enter 16” barrel length. Thanks

There's no consideration for barrel length.

 

[eveyoz]

Ah, that’s no use then.

I have a heavy Palma barrel sitting around that I think would be ok with my AI AT. I have a couple of 24” barrels for it and am having a 20” barrel made, I’d like a short 16” barrel if the 1 in 12 can work for that short length and 168gr projectiles.

 

[JR1200W3]

Ah, that’s no use then.

I have a heavy Palma barrel sitting around that I think would be ok with my AI AT. I have a couple of 24” barrels for it and am having a 20” barrel made, I’d like a short 16” barrel if the 1 in 12 can work for that short length and 168gr projectiles.

What I'm saying is, barrel length by itself won't keep you from stabilizing a bullet. It's about the twist rate, not the length. There's no option to enter barrel length on bergers stability calculator because it's not a factor

 

[Doom]

Stability is a function of gyroscopic stability just like a top. It's all about spin (RPM) which is determined by twist and velocity.

RPM=V*720/T, V=velocity(fps); T=twist (in/rev). The stability calculators do this for you. You simply enter twist and velocity.