308 semi auto load ranges

[timelinex]

I'm trying a bunch of different loads to see what works best in my 20" JP LRP and need some guidance. I tried 175smk with military brass and it didn't do well. I will try to do 175smk in FGMM brass (I have hundreds from shooting factory loads in it)

I need some load ranges to do an OCW for the following combinations:

VARGET (military and federal brass)
1. 168 SMK
2. 155 Palma

8208xbr
3. 175 SMK
4. 168 SMK
5. 155 palma

 

[timelinex]

Ttt

 

[Guest]

I would also throw the 178amax and IMR 4064 into your testing. 178amax is selling for roughly $28.20 per 100 which is cheaper than the 175smk and is more accurate in my AR10 then the 175smk. I've tested 1xHornady Match, 1xFC (FGMM) and 1xLC Military brass and have gotten great results with all three. I picked up 1000 1xLC military brass SS tumbled, deprimmed and swaged cheap so my goal was to find a good load that works with them. I did OCW testing with Hornady Match and FC brass then tested my OCW selected loads in the LC brass and have received great results.

Here's the 2 loads I've developed that are shooting great so far in my testing. I'm now playing with seating depth which I narrowed down to 2-3 with today's testing of the 178amax load.

I'm shooting a POF P308 pinned 14.5" with SWFA SS 5-20x50 HD in AD-Recon mount and SSA-E trigger off front and rear sand bag at 100yds.

178 Amax
43.8gr IMR 4064 (Chargemaster 1500 to 43.5g then Omega II trickled exactly to 43.8g)
1xLC brass FL sized to .004" under fired case size and trimmed to 2.005" (SS tumbled, primer pockets uniformed, flash hole debur, case mouth debur and chamfered)
CCI BR2 primers
bullet seated to 2.1805" ogive measurement using Forster FL Ultra NM Micrometer seating die
Shooting 0.5275" groups at 100yds

175smk
44.3gr Varget (Chargemaster 1500 to 43.8g then Omega II trickled exactly to 44.3g)
1xLC brass FL sized to .004" under fired case size and trimmed to 2.005" (SS tumbled, primer pockets uniformed, flash hole debur, case mouth debur and chamfered)
CCI BR2 primers
bullet seated to 2.2265" ogive measurement using Forster FL Ultra NM Micrometer seating die
Shooting 0.5625" groups at 100yds

All cases were weighed and put in groups within 0.5gr of each other. Same with bullets. Bullet grouping by weight was need for the 175smk due to them varying so much but the 178amax really don't need to be weighed as they are all within .5gr of each other except for maybe 2-3 in the entire box.

It was windy today but both loads have shot in the 0.403"-0.430" range during previous testing. I didn't have the chrono out today but when I chrono these to loads last Friday they were shooting right around 2450-2460 out of my 14.5" barrel.

I highly suggest you perform the OCW test from scratch for your rifle using the Excel spreadsheet, find the 3 charges that have same POI and pick the middle charge then test seating depth. Yours may be completely different than others which I found out the hard way by wasting over 150 loads before doing the OCW test.

OCW Load Development

OCW Microsoft Excel Template

 

[RyeDaddy]

I've loaded a lot of 168's and 155's in gas guns using Varget and 8208 XBR but all in Winchester and Lapua brass.

For working up with those headstamps I'd go 42-44.5gr Varget and 41.0-43.0gr 8208 with 168's,
155's I would go 44.0-46.0gr Varget and 43.0-45.0 XBR.

For Federal/LC brass I would guess decrease charge weights by 1 grain?

Working up to book max loads has proven counterproductive for me in AR's whether piston or DI. It beats the shit out of the brass and the rifles were never as accurate loaded stiffly, if that helps you any.

 

[Guest]

I initially tested 178amax/4064 in 1xFC FGMM brass and 43.5-44.1 was a node. I saw 40g and 43.9-44.5 with Varget/175smk as low and high nodes.

 

[timelinex]

Thanks for the replies guys, it does help.

The reason I don't use the Amax Is simply because I couldn't find a box locally, I wanted to try both 168 and 178.

And I do use OCW as my method.

 

[Guest]

I couldnt find them locally either but online you can get them for around $28/100

 

[bax]

FWI ...

I use LC LR brass. 175 Sierras. Fed 210M. IMR 4064 41.0 grains. COL = 2.800. I have an AR10 gas gun that shoots those at 2,500 fps. It is fun to bang 600 and 700 yard steel at a high rate of fire - the plates really dance.

 

[timelinex]

I've loaded a lot of 168's and 155's in gas guns using Varget and 8208 XBR but all in Winchester and Lapua brass.

For Federal/LC brass I would guess decrease charge weights by 1 grain?

From my understanding, Lapua brass is smaller than Winchester by a grain or two and its got about the same capacity as military brass.

I'm currently using SBS brass. I'm not sorting anything either.

I will try to load a bunch up and see what works tomorrow (if it doesnt rain)

I couldnt find them locally either but online you can get them for around $28/100

I didn't want to have to order even more just to find a load. I'm not looking for insane accuracy where I have to find the absolute best combo. I'm just looking for something that will shoot atleast .5moa (when I do my part).

 

[mkollman74]

My load is as follows:
175 SMK
LC LR Brass
44.4 Varget
FED210M

I do not sort the brass in any way, not even by date. This load had been consistently sub-0.75 MOA in two different large frame ARs, often shooting well below 0.5 MOA. If you do an OCW with these components and start about 43 of powder and work up, you should find the accuracy you desire.

 

[timelinex]

Well this is what I was planning on doing:
Varget powder:

SBS brass 175smk
5x 43.5
5x 43.5
5x 44.0
(double checking nodes I found during initial OCW)

SBS brass 168smk
OCW 42-44.8 in .4gr increments

SBS brass 155gr sierra palma
OCW 44-46.4gr in .4gr increments

FC Brass 175smk
OCW 42.6-44.2gr in .4gr increments

FC brass 168smk
5x 43.5
5x 44.5
(popular loads)

8208XBR Powder:

SBS brass 175smk
OCW 41.2-42.8gr in .4gr increments

SBS brass 168smk
OCW 42-43.6gr in .4gr increments

SBS brass 155gr
OCW 43.9-45.5gr in .4gr increments

I was getting ready to load all this up for tomorrow but I think I just changed my mind. Thats 130 rounds just for some general load testing! Gonna have to think this one through. My AX308 just took me 30 total rounds to find a one hole group load OCW and all. Meh

Edit:

Loaded up all the varget loads for tomorrow. We will see how it goes and I will try to 8208 next time if nothing really shines.