308win question

[rem_kujawa]

Yesterday I took out my rifle for one of our local cold weather matches.I have not shot it since the middle of summer and that load too.The gun shot great at long range,but I was a bit disapointed at my 100yard group.Do you think that the temp makes that big of a difference on group size?

Also I did try sombodys rear rest for my 100 and I did not like could that be it?I switch back to mine and that when it started to shoot great.

 

[rem_kujawa]

Is .003 of neck tension too much I was thinking about .002.

 

[billmo]

In a bolt gun it seems that .002 is a plenty and I try to get down to .0015 if I can. Bill

 

[rem_kujawa]

Im going to try some at .003 and at .002 this weekend if the weather permits,also Im shooting a 175smk with 42.0 grains of varget.Im .005 off the lands.Do you think 43.0 with lapua cases is too much?

 

[Spotcheck_Billy]

You're talking about a neck bushing that sizes .003" smaller than the neck diameter of a loaded cartridge? I think that it's possible that .003" could be too much. I like bushings that are .002" and .001" smaller. You should experiment to find out what seems to work the best for your particular combination.

If your best accuracy comes with 43 gr. of Varget shooting 175 SMK's use that load. I use 44.2 gr. and some shooters that I know use up to 45 gr., all with Lapua brass. YMMV.

You mentioned using a different rear rest. That can alter your shooting style. Anything that you change whether its in the rifle/load combination or your shooting style can and will effect your group size. Ambient temperature can effect accuracy, although Varget is known for being pretty temperature stable. Are you using a new lot of Varget this time?

 

[rem_kujawa]

No same lot of varget.This load was,summer)a one hole group.Now its about 3/4".

I think I have talked to you before spotcheck billy,My loaded round is .338 and I am using the .335,Ill try the .336 one next.

the other thing I did differnt was I did not use the expander ball on this batch.The first time I did because it was new lapua brass.Now they are fire formed and I did not use the ball.

Should I just keep using the expander too.They are Type S dies.

I really think the most of the problem came from the rest.

 

[Spotcheck_Billy]

IIRC your rifle has a custom barrel. If the chamber neck isn't oversize,allowing case necks to expand too much when fired) and your brass neck thickness is consistent you don't need to use an expander ball. I don't use one.

 

[billmo]

Im going to try some at .003 and at .002 this weekend if the weather permits,also Im shooting a 175smk with 42.0 grains of varget.Im .005 off the lands.Do you think 43.0 with lapua cases is too much?

I shot 46.0 gr. of Varget behind a 168 gr. Nosler BT in Lapua cases seated .010 into the lands last time out and saw no pressure signs with my FN SPR .308. Just work up to your max and you will be fine. I think you could drop the expander ball and go to a larger bushing too. Bill

 

[rem_kujawa]

Its a .340 match chamber in a satern barrel.I just want to make sure its not the load and the rest.

Jon

 

[BolloX]

Hi guys,

Just a FWIW. I shoot 44.0 Varget with a Sierra 190MK or Lapua 185 Scenar in 308W,Blaser R93). I also like to run 45.0 Varget with a Berger 185 VLD. No excessive pressure signs in my barrel but YMMV so be carefull.

Cheers from the Eurozone,
BolloX

 

[Bench4fun]

Oh god ya'. The temperatature makes so much difference. If your'e shooting in winter the air is thicker so the bullet has to cut through more, but at longer ranges you bullet has picked up acceleration and therefore is a minority of difference at 300 yards plus, but at 100 yard, you have to make "Winter" adjustments. This is a problem I very recently dealt with for my .243. But at 300 yards I can consistently shoot one inch groups so...I'm content.


Ryan

 

[CatShooter]

Oh god ya'. The temperatature makes so much difference. If your'e shooting in winter the air is thicker so the bullet has to cut through more, but at longer ranges you bullet has picked up acceleration and therefore is a minority of difference at 300 yards plus, but at 100 yard, you have to make "Winter" adjustments. This is a problem I very recently dealt with for my .243. But at 300 yards I can consistently shoot one inch groups so...I'm content.


Ryan

WHAT???

Bullets "pick up acceleration"??? And a "Minority of differences"??

Aw, never mind - I promised the Moderator that I would be good!

Hey Jon-K Don't pay this poopoo no never mind!
Your groups get larger cuz your hands are shaking, cuz you're freezing your buns off


.

 

[rem_kujawa]

That could be it,Im not even old yet and Im already thinking about moving to warmer climate.

 

[billmo]

OK. That is the first I ever heard of that. Let me see if I can figure this out. At 300 yds. in cold weather I can expect my bullet to get another boost of energy because of the air density?
Unless that thing is sliding into another chamber down there and getting a "quick" "real quick" piece of brass, powder, and primer throwed behind it I don't think so. Now this gives a whole new meaning to "Quick Load" boys. Bill