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.

 

[wvfarrier]

I tested 4 more loads yesterday. All were well above book max. No pressure signs (except last load) but called it quits before physics got mad at me.
This was all done with Power Pro 2000MR, CCI 450s and Alpha SRP brass.

47.0- 2706fps avg (group .33")
47.2- 2716fps avg (group .25")
47.6- weirdly 2706fps avg again (.70")
47.8- 2756fps avg (group .55")
This last load has mild primer flattening and a mild ejector mark.

None of the SD's were in double digits.

I am not going to run any of these regularly but it was a fun experiment.

I will say it again though, Alpha Brass is AMAZING stuff.

 

[CaptArab]

Id like to see how far you could take the new eld-vt. Probably not a good rhino bullet but they should fly good.

 

[MK20]

I am working off of long lost memory, so double check me, but I think the original power pro 2000 book max was 47.7

 

[45-90]

Id like to see how far you could take the new eld-vt. Probably not a good rhino bullet but they should fly good.

I purchased 500 174 elvt to test...but was running 177 at 3045 fps in 22" barrel and hybrid cases.
RL 17 was the powder.
2000 MR and RL 17 produce high velocities depending on bullet weight.
I'm working on 375 Raptor and 350 gr SMK which should arrive tomorrow. And 700 gr AP for the 510 whisper which arrived today.

The 174 gr should be over 3100 in the 30" 308 and hybrid csses.

 

[308Gunner]

If you have RL16 you might try it, it gave me a little bit more velocity over Varget.

 

[wvfarrier]

I am working off of long lost memory, so double check me, but I think the original power pro 2000 book max was 47.7

Wow! My hornady manual lists 46.4

 

[wvfarrier]

Ok so i have more updates.

With PP2000MR I made it to 48.4 grains and quit there. I got a mild bolt stick at the very top of the lift, just enough to cause a hitch. Brass still looks good, these 30 pieces are at 9 firings, primers are still tight. I have been annealing after every firing. Also the previous session required trimming about .08 off.
48-averaged 2677 with 1.15" group
48.2- averaged 2683 with .75"
48.4- averaged 2704 and exactly 1" with mild bolt stick

1 more varget load got tested as well.
45.2- averaged 2686 and .89" no bolt issues or brass issues. May try another load of 45.4

 

[wvfarrier]

If you have RL16 you might try it, it gave me a little bit more velocity over Varget.

Unfortuantely its impossible to source locally. I have R17 but I do not think itd suitable for heavies in 308....at least not in the manuals I have.

 

[308Gunner]

Your are right 17 is also not temp stable

 

[45-90]

200 grs is a fairly heavy bullet for 308 and RL 17 is listed there...here's their data for the 200 gr.

I run the 200 gr SMK .715 G1 BC over 2700 fps in a 22" 9 twist Rem Varmint contour barrel in 308 at my mag length with RL 17.

Utilizing modified hybrid cases.

Dangerous...Do Not try these loads in any brass case.
These hybrid cases are made from 6.8x51 hybrid military cases, formed, neck turned, and annealed.
If you reload you can do the same with a little extra work...and ya don't have to run full power loads.

Also run the 230 Atip in the 22" barrel at 2600 fps with RL 17 and hybrid cases.

Set up your short action 308 with longer length detachable mags and 9 and 8 twist barrels...then add hybrid cases for even more velocity.

I have a 30" 8 twist long action 308 running 250 A tips at 2515 fps, 230 grs, around 2700 + fps.

Here's the 22" 9 twist 308 Win light "walking around rifle", shooting 200 gr SMK at mag length....using RL 17 and hybrid cases.

This 200 gr bullet is loaded out longer to over 2900 fps in the long action 30" heavy palma 8 twist 308.
This is my 308 heavy extreme rifle, which has hit 4000 ft/ lbs of muzzle energy.

 

[moosemeat]

How many firing you get on the hybrid cases? Have you had difficulty with them tearing up the actual chamber from the steel on steel contact?
I've been known to push the high nodes in my F T/R rifles from time to time. The juice wasn't worth the squeeze. Cases lasted about 4 firings. Lapua SRP Cases went 6-8. Groups opened up. I dropped back down to normal pressures and my score improved again. They hybrid cases are interesting but I've heard nothing but horror stories about problems with extraction, damaged chambers and short case life.
What's the scoop?

 

[45-90]

How many firing you get on the hybrid cases? Have you had difficulty with them tearing up the actual chamber from the steel on steel contact?
I've been known to push the high nodes in my F T/R rifles from time to time. The juice wasn't worth the squeeze. Cases lasted about 4 firings. Lapua SRP Cases went 6-8. Groups opened up. I dropped back down to normal pressures and my score improved again. They hybrid cases are interesting but I've heard nothing but horror stories about problems with extraction, damaged chambers and short case life.
What's the scoop?

You already decided hybrid cases are not for you...no further discussion is necessary. Don't use them, ...& be happy.

Can't be scaring the chambers because that portion of the case is all brass LOL...maybe .090" in transition from Stainless to brass actually enters the chamber.
So almost all of the S Steel head is hanging out of the chamber so your bolt can grab onto the case head for extraction.

The post is about "more fun with the 308"...there is alot of 308 fun to be had,... hybrid cases are just part of the fun.
I've made hybrid cases for 308, 358, 8.6 blkout, 375 raptor, 6.5 CM, 6 mm Dasher.

How about some accurate 308 subs...or hollow pointed 30 Mauser 86 gr jacketed pistol bullets out of a 30" 8 twist 308.
Inquiring minds want to know...
A variety of calibers with hybrid cases, some with very heavy bullets...including a 308 250 Atip at 2515 fps.

 

[wvfarrier]

I tried some 175 bthps yesterday with PP 2000MR. I, quite literally, ran out of powder capacity before I had pressure signs. Top velocity out of my 20" barrel was 2825fps with a 10 SD and a 5 shot group of .66". It did stretch the case necks by an average of .013

I am going to try this same load with the 180 grain Sierra Gamekings once they arrived

 

[supercorndogs]

I am working off of long lost memory, so double check me, but I think the original power pro 2000 book max was 47.7

.1g before ejector marks is still well over pressure. Especially in rifles with long throats that tend to mask pressure signs.

 

[supercorndogs]

How many firing you get on the hybrid cases? Have you had difficulty with them tearing up the actual chamber from the steel on steel contact?
I've been known to push the high nodes in my F T/R rifles from time to time. The juice wasn't worth the squeeze. Cases lasted about 4 firings. Lapua SRP Cases went 6-8. Groups opened up. I dropped back down to normal pressures and my score improved again. They hybrid cases are interesting but I've heard nothing but horror stories about problems with extraction, damaged chambers and short case life.
What's the scoop?

That is a good question, especially the way stainless likes to gal.

 

[45-90]

That is a good question, especially the way stainless likes to gal.

"Stainless likes to gal"??
" gal"... is a girl... according to the dictionary.

 

[supercorndogs]

"Stainless likes to gal"??
" gal"... is a girl... according to the dictionary.

This from the guy who said using nickle plated brass would mess up your chamber.

Couldnt figure out what it meant because of a L? Never took you for being real sharp, I guess.

I meant stainless likes to gall. Do you disagree?