New .308 AI load development **Getting There, Updated**

[03psd]

I hit the range this morning to start load development of my new AIAT. It has a 17" Bartlein 10 twist barrel. I want to use 175gr SMK because they should do all I need out to 1k and seem to be the sweet spot between performance, cost, and availability especially since a ton of guys are dumping .308 for 6.5.
I used both Varget and IMR 4064. With the Varget I started at 44.0gr and worked up in .2 increments to 44.8gr. With the 4064 I started at 42.0 and worked up in .2 increments to 42.6. Pics of each target are below. All where 3 round groups in each charge weight.




The Varget has me most confused. The one shot in the 44.2 group I know I jerked so that may be the best of the 5 groups but none are really that bad or that great. All at 44.2 and above are sub moa. The 44.8 maybe the best.

The IMR 4064 is my go to powder for .308 My custom rifle loves 43.0gr under a 168gr SMK but its a 11 twist. Obviously the 42.2-42.4gr looks pretty damn good. I will load some 5 round tests for those charge weights for my next outing.

I keep hearing how great Varget is and I have several pounds of it, bought because of the hype, but frankly it looks like the 4064 is going to be my go to powder for this new AI rilfe as well. I will play a little more with the Varget if someone, more knowledgeable than I sees something in this target worth pursuing.

 

[GhengisAhn175]

You started too high hoping to run into a high node. Start 2 grains lower for each and work up.

you also didn't state your seat depth or jump distance. Needs to be fixed and as long as possible so when you do seat depth tests you just seat deeper.

4064 and varget are both great powders; wouldn't hesitate to use either or regardless of temp sensitivity

 

[03psd]

You started too high hoping to run into a high node. Start 2 grains lower for each and work up.

you also didn't state your seat depth or jump distance. Needs to be fixed and as long as possible so when you do seat depth tests you just seat deeper.

4064 and varget are both great powders; wouldn't hesitate to use either or regardless of temp sensitivity

I loaded them all to a COAL of 2.85". I am going to be limited by mag length I would guess but they can go a touch longer then where I started. Are you suggesting I try having them touching the lands? I am a novice handloader so pls keep that in mind with what are bound to be rookie questions. Thanks!

 

[GIXXER2000]

I shoot a 20 in 1-12 Bartlein . I was shooting the 175 SMK but switched to 178ELD-X ( the ELD-M weren't available yet) and am getting 1/2 to1/3 moa groups. Have shot out passed 1000 yards with very good accuracy. The cost is about same for both bullets. Don't get me wrong I like the SMK but the ELLD-X just shot better in the AT. Good luck !!
Brass Lapua
Primmer CCI BR-2
Varget 43.1
AVG FPS 2636
C.O.A.L 2.865.

 

[Marksman10x]

42.2, 42.4, and 42.6 all have about the same point of impact, indicating an accuracy node. I would play around with 42.4 and see what happens.

 

[Marksman10x]

Also, 42 grains looks like a scatter node.

 

[L.R.Novice]

How did you choose the starting loads? Varget and 4064 book loads are similar yet you started much higher with Varget. My suggestion is you start lower with Varget. I've found a 175 SMK over 43.5 grains of Varget to be a common accuracy node in multiple 308s.

 

[Marksman10x]

I've found a 175 SMK over 43.5 grains of Varget to be a common accuracy node in multiple 308s.

I've also found this to be true

 

[03psd]

How did you choose the starting loads? Varget and 4064 book loads are similar yet you started much higher with Varget. My suggestion is you start lower with Varget. I've found a 175 SMK over 43.5 grains of Varget to be a common accuracy node in multiple 308s.

thanks for the input. I am going to back off 2 gr and build up with the varget to see what happens. The 4064 looks good in the 42.2-42.4 range so I will explore that a bit more. my other 308 prefers 43.0gr of 4064 so I started a bit lower than that and worked up. the varget starting point was an internet suggestion. i know, i know...... i dont have a chronograph so I have no idea what MV any of these loads produce or the SD. Once I get something that shoots well consistently I plan on getting a labradar and seeing what the performance is.

 

[GhengisAhn175]

That's fine to start at mag length minus 20'thousandths or so which will allow you room to chase the lands later. Stay at mag length minus 20 and run a powder charge test. You should find something good and not wed to adjust seat depth

 

[supercorndogs]

What brass? 42.4 of varget with Lapua brass and a 175 smk .02 off the lands average velocity 2620fps, is where mine likes it. I get another 100fps with RL15 over Varget.

 

[03psd]

What brass? 42.4 of varget with Lapua brass and a 175 smk .02 off the lands average velocity 2620fps, is where mine likes it. I get another 100fps with RL15 over Varget.

I was using RP brass. I have some quality brass such as Prime, Laupua and Hornady Match but I generally use whatever I have in quantity and priced right. I know certain brass is better than others but I do FL resize, chamfer, deburr, cut to length, etc. I was told brass was fairly far down on the list of things that improve performance. It definetly does but there are other things that I need to figure out before I think brass manufacturer will be the limiting factor.

 

[supercorndogs]

I was using RP brass. I have some quality brass such as Prime, Laupua and Hornady Match but I generally use whatever I have in quantity and priced right. I know certain brass is better than others but I do FL resize, chamfer, deburr, cut to length, etc. I was told brass was fairly far down on the list of things that improve performance. It definetly does but there are other things that I need to figure out before I think brass manufacturer will be the limiting factor.

The only reason I mention brass is internal capacity. My loads a different for Lapua, Winchester, and Hornady Match brass. The thing that alines on all off them is velocity.

 

[WirgmanUSMC]

To echo what others have said, 44gr of Varget is too high to start with. I always start my .308 175gr Varget loads around 42.8 or so and work up.
Currently I'm running 43.7gr of Varget, 175gr Berger OTM Tactical out of Lapua brass, 210GM primers, 2.865 OAL, with a .02 jump. 20" HawkHill 1-9 barrel, 2650fps and .5" groups all day.
Up at 44gr they shot alright, but started to get a little sticky and the groups were opening up a bit. Didn't wanna push my luck in pressure up to the next accuracy node.

 

[03psd]

Ok so heres my update. Using Varget only I loaded 5 rounds of each charge weight starting with 42.0 and increasing .2gr up to and including 43.8gr. FC 2x fired brass with standard prep, CCI 200 primers and 175gr SMK, 2.85" COAL was used for all. 50 rounds total.

It looks like backing off to 42gr was great advice. I think between 42.2 and 42.8 maybe a sweet spot. The one shot just right of the bull at 42.4gr was me jerking the trigger. Above 43gr things opened up except for 43,.8 with 4 shots in a cloverleaf. The 1 shot left of bull hasgot to be a push althought I dont recall it at the time. Its the furthest round left of bull out of all 50 and with the other 4 at the same charge weight right of bull in a cloverleaf, I am skeptical.

I appreciate the advice and welcome all feedback.

 

[WirgmanUSMC]

Looking much better. I would now play around that 43.6-43.9 range in more detail. Do loads every .1. That is a super popular node range for tons of .308 loaders. Your 43.8 group didn't look bad, but your 43.7 might be even better

 

[eicas]

I will also echo much of the above. I have a 700 5R and have also settled on the 175smk over various Bergers and Hornadys. They just seem to like the gun. My best loads are Varget at 42.3 and RE15 at 43.2. Im jumping both loads .010". While neither melt the atmosphere, they are solid performers out to 1K. Another good load for me has been the MK118 repro using the same SMK and 43.6 of RE15. These Im loading 2.282". While not as accurate as either of the .010 jump loads, I can magazine feed them and they are pretty close.

 

[03psd]

I will also echo much of the above. I have a 700 5R and have also settled on the 175smk over various Bergers and Hornadys. They just seem to like the gun. My best loads are Varget at 42.3 and RE15 at 43.2. Im jumping both loads .010". While neither melt the atmosphere, they are solid performers out to 1K. Another good load for me has been the MK118 repro using the same SMK and 43.6 of RE15. These Im loading 2.282". While not as accurate as either of the .010 jump loads, I can magazine feed them and they are pretty close.

2.282" must be a typo.
I appreciate the different loads for different powders but I hope to find one that works better then I can shoot and stick to it. If less than 43gr of Varget can get me out to 1k, then I will be a happy camper. I have no idea what the MV with 42.3gr would be but its got to be <2500 FPS, no?

 

[eicas]

Hey...sorry for the typo. Just another reason to be wary of idiots on the internet . It should read "2.820" COAL. The CBTO measurement is 2.225".

Velocity with the 42.3 Varget load is about the same as the RE15 but I dont have it in my notes for some reason. I just shot both loads Saturday and the RE15 data I also used for the Varget loads at 600yds. Shooting 12" square and 6" steel with same POI. My data shows 2545fps@about 3000DA on the RE15 load.

I messed around with a ton of bullets before going back to the 175smk. Played with everything from 155gr up to the 185s. Sometimes the ogives on the SMKs are a bit "wandering" but it doesnt seem to matter. I had originally gone to the Bergers for their consistency on this, but despite them being perfect and pretty, the gun just doesnt like them as much. I also began to mess around with 2000MR. I had a SMOKING load running 2750-2800 (honest...measured with a known good Magnetospeed) but kind of backed off and stopped going that route. I felt that eventhough I wasnt really seeing pressure signs with the loads, I had to be beating the gun up pretty bad. Just not what I was after. Ive had the above 43.2/RE15 load out to 1K successfully and figured if I want to push harder I need a different platform. There is a thread here somewhere on a guy who also played with the 2000MR. I think he was using the 185s too however.

Happy shooting!

 

[03psd]

Hey...sorry for the typo. Just another reason to be wary of idiots on the internet . It should read "2.820" COAL. The CBTO measurement is 2.225".

Velocity with the 42.3 Varget load is about the same as the RE15 but I dont have it in my notes for some reason. I just shot both loads Saturday and the RE15 data I also used for the Varget loads at 600yds. Shooting 12" square and 6" steel with same POI. My data shows 2545fps@about 3000DA on the RE15 load.

I messed around with a ton of bullets before going back to the 175smk. Played with everything from 155gr up to the 185s. Sometimes the ogives on the SMKs are a bit "wandering" but it doesnt seem to matter. I had originally gone to the Bergers for their consistency on this, but despite them being perfect and pretty, the gun just doesnt like them as much. I also began to mess around with 2000MR. I had a SMOKING load running 2750-2800 (honest...measured with a known good Magnetospeed) but kind of backed off and stopped going that route. I felt that eventhough I wasnt really seeing pressure signs with the loads, I had to be beating the gun up pretty bad. Just not what I was after. Ive had the above 43.2/RE15 load out to 1K successfully and figured if I want to push harder I need a different platform. There is a thread here somewhere on a guy who also played with the 2000MR. I think he was using the 185s too however.

Happy shooting!

Is it 42.3 or 43.2 ??

I am guessing 43.2 as theother would seem pretty light but I could be wrong.