Small primer vs large primer .308

[Cnewhouse48]

First off it’s been a while since I’ve been active here so hello again guys.

I picked up a savage 12fv In .308 a while back and have been doing some good load device and have had good LR shooting with it. I’m not new to it I’ve just been out a while.

Anyways I had a good load using 43gr imr4064 in Lapua cases using 178 hornady BTHP and wlr primers@2749 the group was constant 3/4” group. But my SD and ES were very high.


I recently purchased a batch of starline match .308 brass with small primer pockets, and started my load development.
I started at 43.0gr imr4064 Same load as my original using both BR4s and 450mags, my MV was only around 2510 with the 450/ and 2650 with the BR4 SD and ES were great but group wise not good.

I went back and did a load development from 43-45 grains and hit very light pressure at 45grns however my best group was only about 1moa@100yards.

So my question is what do you think is the issue? I hit the same velocity as the other load but it never tightened up. I’ve checked the gun all is good and tight. The only thing I can think to do is keep changing primers. Anyone experience something like this?

Since switching to starline brass all my SD have been under 12fps and es under 20 when before I’d have huge numbers like es of 40-60 and sd of 20

 

[XLR308]

Inconsistent neck tension maybe.
Have you anneled the Starline brass ?
Are you using an expander mandrel after sizing ?
What sort of run out are you seeing on your loaded rounds ?
My pet load with Lapua Palma brass, 40.7gr of AR-COMP, CCI450, 178amax at 2.885" and 2650fps will easily hold .5"-.6" MOA at 100 yards from a Rem700 SPS Varmint. Not cherry picked groups that's the best the rifle does with me steering it for consecutive five shot groups.

 

[Cnewhouse48]

Inconsistent neck tension maybe.
Have you anneled the Starline brass ?
Are you using an expander mandrel after sizing ?
What sort of run out are you seeing on your loaded rounds ?
My pet load with Lapua Palma brass, 40.7gr of AR-COMP, CCI450, 178amax at 2.885" and 2650fps will easily hold .5"-.6" MOA at 100 yards from a Rem700 SPS Varmint. Not cherry picked groups that's the best the rifle does with me steering it for consecutive five shot groups.

This is my very first load on the starline all I’ve done is run it over a expander ball chamfer and debur it.
I have no idea on the run out to be honest.

 

[Huskydriver]

+1 on the neck tension. What kind of FL die are you using is it a bushing die?

 

[Cnewhouse48]

+1 on the neck tension. What kind of FL die are you using is it a bushing die?

Standard lee fl I need to get bushing dies. I’m not sure it’s neck tension because I’m using the same dies different cases and primers. IMO if it was neck tension wouldn’t I be seing erratic sd and es?

 

[Huskydriver]

Yes this can be caused by the brass becoming work hardened. That's why guys anneal to soften the necks so hopefully you can control neck tension so it's consistent from reload to reload. Also why bushing dies are huge. Less working off the brass and you can control the neck tension better.

 

[XLR308]

Just read through your OP again, if you were using virgin brass for load development I personally would scrap it and start over with you fired cases.
There are to many inconsistencies with virgin brass in my opinion to trust the ressults.

 

[Cnewhouse48]

Just read through your OP again, if you were using virgin brass for load development I personally would scrap it and start over with you fired cases.
There are to many inconsistencies with virgin brass in my opinion to trust the ressults.

Even if I’m full length sizing?

 

[XLR308]

Even if I’m full length sizing?

Yes and even with the premium brands of brass.
I wouldn't personally but that's me, I've read plenty about people just taking new Lapua brass from the box and loading with great results but that's mainly in 6mm BR in match chambers that are cut very close to the brass dimensions.
Not sure what your chamber specs are or how well that matches your new brass but I would trust the fired brass more that has had the shoulder bumped .002" for load development.
I have allways had better results on the second firing of brass.

 

[Cnewhouse48]

Yes and even with the premium brands of brass.
I wouldn't personally but that's me, I've read plenty about people just taking new Lapua brass from the box and loading with great results but that's mainly in 6mm BR in match chambers that are cut very close to the brass dimensions.
Not sure what your chamber specs are or how well that matches your new brass but I would trust the fired brass more that has had the shoulder bumped .002" for load development.
I have allways had better results on the second firing of brass.

Ok thanks that’s encouraging. I’ll be looking for a neck bushing die as I already had planned to do so. I normally just load for gas guns and have had decent results fl sizing I’ll continue to play with this load and get it re-figured out.

 

[XLR308]

Ok thanks that’s encouraging. I’ll be looking for a neck bushing die as I already had planned to do so. I normally just load for gas guns and have had decent results fl sizing I’ll continue to play with this load and get it re-figured out.

FL sizing is fine as long as your not working the brass excessively and just bumping the shoulder back enough for reliability and smooth chambering.
A full length bushing die is a good choice as well and if you want to neck size I have had very good results with the Lee collet neck dies.
Just depends on what you want and how much you want to spend.

 

[Cnewhouse48]

FL sizing is fine as long as your not working the brass excessively and just bumping the shoulder back enough for reliability and smooth chambering.
A full length bushing die is a good choice as well and if you want to neck size I have had very good results with the Lee collet neck dies.
Just depends on what you want and how much you want to spend.

Well I’m cheap lol always rather spend less if possible but I also don’t want to buy twice.

 

[XLR308]

Well I’m cheap lol always rather spend less if possible but I also don’t want to buy twice.

The Lee collet neck dies a pretty cheap and load some very straight ammo when set up and used properly and do not overwork the brass.

 

[Cnewhouse48]

The Lee collet neck dies a pretty cheap and load some very straight ammo when set up and used properly and do not overwork the brass.

So I’ve been looking at does and the collet die seems to be prettt simple to use, if I understand correctly I would just use it to neck size my brass then every few firings bump the shoulder back down just to ensure proper chambering. Or should I run the brass through a body die the a lee collet die?

 

[XLR308]

So I’ve been looking at does and the collet die seems to be prettt simple to use, if I understand correctly I would just use it to neck size my brass then every few firings bump the shoulder back down just to ensure proper chambering. Or should I run the brass through a body die the a lee collet die?

Only use the body die when you start to notice resistance opening the bolt on a fired case.
The load I listed above I will get 3-4 firings before that point, if you are running loads that are warmer it will obviously be sooner.
Mine is listed at Alliant book max but I am running a longer COAL than listed with a very generous freebore in Lapua Palma brass so in my rifle it's a pretty easy load on the brass.

 

[Cnewhouse48]

Only use the body die when you start to notice resistance opening the bolt on a fired case.
The load I listed above I will get 3-4 firings before that point, if you are running loads that are warmer it will obviously be sooner.
Mine is listed at Alliant book max but I am running a longer COAL than listed with a very generous freebore in Lapua Palma brass so in my rifle it's a pretty easy load on the brass.

Thanks for the help. I loaded another ladder last night and I’ll shoot them soon I just want to verify that it’s the load and not me.

 

[Cnewhouse48]

Finally got around to shooting my loads and I figured out the issue, i shot my original load and had terrible results so I cleaned the gun and wow what a difference. I probably had 150 rounds between cleanings, I’ve never had a gun open up like that before.

I had some pretty good results at the range best groups were with 44.5-45gr of imr4064 and br4 primers.