Gunsmithing 30-378 accuracy potential

[nuclabuyer]

I have a Sako M995 that my wife bought me about 3 years ago and I wanted a long range gun so I bought the 30-378 thinking it shoots flat, can push the heavy bullets good etc. I have added a 32" Pacnor med Palma Contour (1-10 twist i think, I told Pacnor to make it for 210VLD)they also did a time and true to the action, its glass bedded in a Mcmillan A-5. Has a muzzle break and weighs 18lbs so the recoil is that of a 243 and I know I shoot better then the accuracy I am getting. It currently has a nightforce 12-42 power I use for load development.
I have shot 185 and 210 berger vld along with 208 amax and the 230's. I have tried Retumbo, H-1000 and R-25 with different primers, seating depth etc and with about 300 shots of different combo's through the barrel, I can get the 185 vld's at about an 1" at 100 as the best so far.
Is there any inherent accuracy problems with this caliber? Any reason I am expecting to much? I have a 338 edge that will shoot circles around this thing. I am concerned that if I go with the same caliber that I will waiste about $500-600 and end up with the same results. Any ideas??

 

[JJones75]

Re: 30-378 accuracy potential

how much free bore does it have ? I have a old 300Wby with a mile of free bore and it shoots it's best with a 220g SMK seated WAY out and pushed REALY hard

maybe try heavier bullets like the 240's , that case with that much barrel should get you to 3000 fps and that bullet at that speed will go a long fuggin way !!

are you shooting fire formed brass?

 

[LRI]

Re: 30-378 accuracy potential

FWIW when the 1K plus thing started becoming more popular about 10-12 years ago a numer of folks turned to fiddling with the 30-378 WBY. There's been a few noteworthy accomplishments with the cartridge.

With that in mind its capable of shooting well. Its just a matter of finding the right setup. Ultra high performance cartridges have quirks as with anything taken to extreme limits. 100+ grains of powder funneled down a 30 caliber hole is a lot to manage.

As you mentioned the 338 Edge is far more forgiving.

That said it boils down to a simple question: are you a shooter or are you a fiddler?

Meaning do you want positive trigger time or do you prefer to tinker at the reloading/gunsmith bench just for the enjoyment of it?

There's no right answer. The answer that's right for <span style="font-weight: bold">you</span> is what matters.

Good luck.

C.

 

[matchking]

Re: 30-378 accuracy potential

I used to have a rifle chambered in 30-378 WBY and it was very accurate. I ran 165 and 180 grain bullets with H50BMG with excellent results. It would shoot sub-moa with factory ammo as well.

 

[nuclabuyer]

Re: 30-378 accuracy potential

There is minimal freebore according to pacnor. I had to send the barrel back to them to have them add a touch more freebore because I was getting high pressure with everything I reloaded including factory ammo. I had to open the action shooting factory ammo with a ball peen hammer.
I do like to tinker and mess around with reloading alot but generally speaking I tinker to get the last little bit of accuracy out of something and once I get the tinking done I like to shoot it. I dont generally mess with loads that shoot 2" at 100. That dosent have any hope, I could be wrong about that, but generally I shoot in .5 increment on these bigger calibers, then I move the bullet seating depth .30 at a time.
I am different then most people. The more money I dump in a gun, the worse it shoots. I really want to send this to you chad and let you give it a run through. I would like to shoot 208 amax or a 210 vld etc

 

[2156SMK]

Re: 30-378 accuracy potential

There is a chance that those big bullets are just not settling down at 100yds.
Shoot some groups at 200 or 300yds and see if the groups don't end up being smaller in angular size than they are at 100yds.

I have seen that to be common with 30cal bullets above 190gr and with the 300gr 338's.

 

[nuclabuyer]

Re: 30-378 accuracy potential

I have thought that and have taken some reloads that are a touch over an inch and they end up shooting even worse are 300. I am to the conclusion that something isnt right with some part of the gun. I can run 1 moa at 100 and 3 in at 300 with 116gr of 50BMG and a 185 vld. The amax 208's and target 230 shoots about 1 1/2" at 100 and 4" at 300. I have 300+ bullets down this barrel with 1" being the best, if i keep shooting looking for the right combo the barrel will be done for about the time I find something. I am thinking if I ship it to Chad, he can run though it and see if it is off somewhere. Either something the Pacnor did or something that I did. Not blaming anybody yet, just have a 2nd opinion.

 

[2156SMK]

Re: 30-378 accuracy potential

Have you tried another scope?

 

[nuclabuyer]

Re: 30-378 accuracy potential

I havent tried another scope on this gun but I did move this scope/ring combo on to my 6mm Dasher and it shoots like most 6mm BR and Dashers, 1/4 moa usually at both 100 and 300 yards. After that I went from Opti-lok ring/base combo to a Rodale 1pc base with no change in accuracy.

 

[DAVETOOLEY]

Re: 30-378 accuracy potential

I build a few LW hunting rifles in that caliber and have no problem getting them to shoot sub .5 MOA. Something's not right.

 

[Twitch2120]

Re: 30-378 accuracy potential

Who did your brake? Something there might be directing gas funny and causeing something bad. Check the crown as well. Someone might have buggered it up.

 

[nuclabuyer]

Re: 30-378 accuracy potential

it was all done at once by Pac-Nor.

 

[matchking]

Re: 30-378 accuracy potential

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: nuclabuyer</div><div class="ubbcode-body"> I have 300+ bullets down this barrel with 1" being the best, if i keep shooting looking for the right combo the barrel will be done for about the time I find something. </div></div>
Better find the load quick!!

 

[Roskoe]

Re: 30-378 accuracy potential

I have built a couple of these using Hart 28" barrels and they would both shoot in the 1/4" range. Nothing inherently wrong with the caliber. But playing around with loads at length can get old when the useful barrel of the rifle is less than 800 rounds.

 

[xXlojackXx]

Re: 30-378 accuracy potential

When I develope loads I never increase more than .2gr's up or down between different loads. For instance, I have a .300 that lovs to shoot 89.1gr RL25, and if I go to 89.3 or down to 88.9 it will start to walk on me. So try decreasing the jumps you are making with powder charge, as you could be skipping over the sweet spot for your rifle with .5gr increments.

 

[Mech45]

Re: 30-378 accuracy potential

I used to have a Weatherby in 30-378 with the factory muzzle brake. The load it liked best was a 180gr SMK, 50BMG powder and Federal 215 primer. OAL was the max the magazine would allow, it would shoot under a inch for five shots at 200yds. Is the 1/10 twist enough to stabilize the heavier bullets?

Chris

 

[nuclabuyer]

Re: 30-378 accuracy potential

Generally I will go to the .2 increments but I have not ran into a caliber yet the will shoot a 1 inch group at a given load, say 116.5, and have it be that dramatically different at 116.2. If I was shooting a 3/4" group or a 1/2" group I would take the load shooting the best group in the .5 increments and break it down a little further to the .2's, say my known good load and then +/- .2 and +/- .4 to find the sweetest load available.