More fun with 308 Win

[wvfarrier]

I have been doing more testing and toying with 308.

I have been using Alpha small rifle primer brass and CCI 450 small rifle magnum primers.

Rifleis a Zermatt Origin with 20" PVA M24 profile 1:10 twist.

MDT ACC Chassis.

My goal was 3000ft lbs of energy at the muzzle. This was due to a conversation I had with a buddy who just came back from a Safari. The company had a 3000ft lbs, at the muzzle, requirement for any rifle used for plains game. He took a 300wsm.

Powders were Varget and Power Pro 2000mr.

These loads are above book max but showed no pressure signs. I annealed every other firing. I worked the book pressure loads up using annealed starline srp brass.

I forgot to get pictures of the varget loads.

#1- Averaged 2605fps and .30" 5 shot group (No pressure Signs)

#2- Averaged 2614fps and .65" 5 shot group (No Pressure Signs)

#3- Averaged 2627fps and .88" 5 shot group (Very faint ejector mark)

#4- Averaged 2635fps and .55" 5 shot group (Again faint ejector mark, easy bolt lift)

#5- Averaged 2644fps and .23" 5 shot group (Ejector mark and at the very top of the bolt lift it was mildly sticky at the very top)

Power Pro 2000mr was a little lacking in the velocity dept.

My max load of 46.6 grains topped out at 2635 but should have been faster. My thought is that I am not getting complete powder burn. I found some partially burnt kernals in the barrel
.
The 46 grain load was absurdly accurate and had an average velocity of 2615.

My 1moa sticker fell off the hole it was covering so I just shot at the hole.

 

[MK20]

Run the Sig 6.8 hybrid cases and you will hit your mark.

 

[gopherslayer]

Muzzle energy means jack shit. I wouldn’t hunt with an outfit like that.

 

[MK20]

Of course it is stupid. Most African caliber rules are. What do you expect. It is a continent where they still murder and rape each other for fun or because someone got offended.

But remember, all will be well if you just "Kill the Boer, the farmer."

 

[CaptArab]

I can't hardly read that black font on dark mode but did I miss the part where you said what bullet you're shooting?

 

[Thump_rrr]

I can't hardly read that black font on dark mode but did I miss the part where you said what bullet you're shooting?

It has to be a 200gr to get to 3000ft lbs. at 2625fps

 

[45-90]

3000 ft/lbs is doable in a 308 Win.
I have ran up to 4000 lbs in muzzle energy with a 30" 8 twist long action...and hybrid cases.
The 30" standard load with Lapua brass LR primer 2000MR 200 gr SMK is 2865 fps.
It does 2740 fps in a 9 twist 22" single load short action.

A 20" is on the short side for velocity, a 22" seems to be a good compromise for getting decent velocity.

So it all depends on what bullet you want to shoot, mag length, case type brass or hybrid.
Here's the 22" 308 with SA MDT mag length 2.970" 212 gr eldx at 2700 fps in load development, and 200 SMK in the mag 2700 fps, and 230 Atips at 2600 fps 9 twist 22" ...but with hybrid cases.

 

[wvfarrier]

My bad, 195 grain TMK, 2.86" OAL

 

[wvfarrier]

3000 ft/lbs is doable in a 308 Win.
I have ran up to 4000 lbs in muzzle energy with a 30" 8 twist long action...and hybrid cases.
The 30" standard load with Lapua brass LR primer 2000MR 200 gr SMK is 2865 fps.
It does 2740 fps in a 9 twist 22" single load short action.

A 20" is on the short side for velocity, a 22" seems to be a good compromise for getting decent velocity.

So it all depends on what bullet you want to shoot, mag length, case type brass or hybrid.
Here's the 22" 308 with SA MDT mag length 2.970" 212 gr eldx at 2700 fps in load development, and 200 SMK in the mag 2700 fps, and 230 Atips at 2600 fps 9 twist 22" ...but with hybrid cases.

Agreed on the barrel length for sure. Must admit though....I really enjoy this rifle. I have another action that may end up with a longer barrel on it.

 

[45-90]

You may get 3000 ft-lb with these loads I use in a 16" 6 lb AR 10... if your 20" can pick up around 100 fps in 4 more inches of barrel.
Set your rifle up for sucess MDT detachable mag without center plate will feed 2.990" cartridges...2.860" is losing performance are the short barrels.

I lost over 40 fps per second using Small Rifle Primers in Lapua Palma brass over their standard LR primer brass...depending on the powder ya lose velocity with SR primers especially when using 50 grains of powder...ya have to add more powder with SR primer to get the same velocity, and S/D s are much better with heavy loads... SR primers are OK in warm weather and target loads with easier to ignite powders.
So I do not use SR primers in high performance loads.

Here are some lighter bullet loads that worked in my 16" AR 10 with 2.855" cartridges. With 4" of extra barrel you'll might reach 3000 ft-lbs.
Another example AR 10 200 gr SMK .715 g1 BC 2673 fps out of 18" AR 10 single load.

Its how you set up a 308 that gets 3200 to 3400 ft-lbs in 22" or 3600 to 3800 ft-lbs in a 30" long action...and more.
My 22" was built for $600, I chambered the new Rem Varmint contour 5R 9 twist barrel for heavy bullets 200 to 230 gr and a bunch of used parts...inleted for detachable mag , MDT detachable mag for 2.990" and muzzle brake...just "normal everyday 308 builds", that most gunsmiths do, you're missing out on a lot of extra performance.

I've built 8 308s from 16" to 30" and twists from 12 to 8 twist, light barrels to heavy palma...even hybrid cases...lots of experimentation with the 308.

Work up... use at your own risk.