Help me solve this 338 Lapua Mag problem

F

fireguyty

New member
Ok, so before I get to my problem, let me explain my reloading process. When I reload for a new caliber I like to shoot all the powders that I have for any given bullet weight at 2 grains below the published max. This way I can see the best combination of accuracy and speed out of all the powders that I have before I go to the next step of refinement. I fire these in round robin style to equally distribute any variances (barrel fouling, heat, etc).

In this case I have a new Desert Tactical Arms SRS in .338 Lapua Magnum. Loading 300 grain Lapua scenars with new Hornady brass and Remington 9 1/2 M primers. I fired the following powders round robin @ 100 yards in this order:
Winchester Supreme 780
Reloader 25
Hogdon H1000
IMR 7828
Hogdon Retumbo

Grouping went as follows starting at the 2nd bullet:
S 780 two shots 1.5"
RL 25 two shots .6"
H1000 two shots .9"
IMR 7828 two shots 1.7"
Retumbo two shots 1.7"

Starting with the 3rd bullet each 3rd shot was significantly high at somewhere between 4-5 inches and was generally in the same spot for three of the powders, and the same 4-5 inches off for the other two, but high and left.

After the third shot with the H1000 I started to expect something was wrong and looked through the barrel to find a lot of fouling.

My theory is that one of the 5 powders is very dirty and started to affect my accuracy somewhere between the 2nd shot with the H1000 and the 2nd shot of Retumbo. Are any of these powders extremely dirty?

I have done this method of powder testing on at least 6 different rifles in my first stage of load development. Is this a bad idea?

Any help would be appreciated.

Ty
 
stick with one powder working up loads .then change if you dont get the results your looking for.r25 has always been my goto powder.its never let me down.
 
By shooting a round robin with your different powders you cant tell the bad apple of the bunch. Shooting them one at a time will most likely sort it out. You could shorten it by shooting simple 3 shot groups over a chrony. Of the 4 powders one surly would stand out with higher velocity or good average with better accuracy than the others.

So after 8 rounds you start to throw them, is it the rifle, scope or shooter getting a little recoil sensitive?

Would it throw the 9th shot if they all were the same load?
 
Originally Posted By: FurhunterBy shooting a round robin with your different powders you cant tell the bad apple of the bunch. Shooting them one at a time will most likely sort it out. You could shorten it by shooting simple 3 shot groups over a chrony. Of the 4 powders one surly would stand out with higher velocity or good average with better accuracy than the others.

So after 8 rounds you start to throw them, is it the rifle, scope or shooter getting a little recoil sensitive?

Would it throw the 9th shot if they all were the same load?

All good points. I don't think its the scope (Nightforce on Larue mount), and not only am I not recoil sensitive, it doesn't kick. It very well could be the rifle, but with the price I paid for it, I hope not.

I think I'll reroll RL 25, H1000, and Retumbo. The two former because of accuracy and the latter because of sheer speed, and shoot all three together.
 
I like to load 10 loads with each powder with the same bullet. When I shoot to see how they group I'll Shoot 5 and Clean the barrel and let it cool down then shoot the other 5 and do the same. Then switch to another load. I have found that you will have one stand out on accuracy when you compare targets.
 
I think your right on concentrating around H1000/RL25/Retumbo. I would reccomend to go the H1000/Retumbo route myself for a couple of reasons. For one, its an extreme series powder and is not temp sensitive, unlike RL25. For two, there pretty clean burning powders, also pretty good for lot to lot consistency, (a lot better then RL25 anyways).

I shoot a 338 EDGE w/300g SMKs and H1000 at 2825fps, basically a 338 Lapua. Its very accurate and consistent load. I usually only clean when I notice the accuracy dropping off and thats usually anywhere from 80-100 rounds. I've got around 300 rounds down the tube now and think I've cleaned it 3 times, it shoots pretty dang good, just scored 2 out of 3 hits on about a 20" rock at 1175 yards last week while up in the mountains. Cleaning every 5 or 10 shots is an unneccesary process in my opinion.

I usually work with 2 powders at a time, anymore then that and it gets kinda hectic, but everyone does things differently. I also dont shoot round robin. I pick a powder, shoot the loads from the middle on up to max (3 shots with each load), then go to the next powder and do the same. I give a minute or two inbetween shots, works for me.

Let us know how things go with your new batch of loads.
 
Good stuff.

I have been doing nothing but reading this morning, and have come up with a couple of things. H1000 is regarded as cleaner and less temperature sensitive than the rest. Also I have been loading these Scenars right at the lands, and most say to be back .01-.015.

At this point (could change in five minutes) I'm gonna OCW test H1000 with 5 charges at 90.6-91.4 and lengthen the jump to .01". 91 was the group that started off good with around 2800 fps.

I appreciate the help and will let you guys know how it goes.
Ty
 
Most guys are having really good accuracy with the 300g SMK out of the EDGES and Lapuas at around 2750-2850fps depending on bbl length, etc, so your right in there. I love H1000, I've burnt a lot of it through the 300 RUM and 338 EDGE, and now my 7 RM. I've tried Retumbo in all 3 of the above rifles as well and although I do get higher velocities usually 50-75fps, it has not been as accurate or consistent for me as H1000.

Definately keep us posted.
 
I would not recommend starting at 2 grains shy of a Maximum charge. If you do that often enough, one day you may find just the right combination of powder, primer, case, bullet, chamber and barrel that is just right (or wrong as the case may be) and hurt yourself or at least blow up a gun.

Should you not start at least 10% below max?
 
Yes, I agree that with a factory rifle/action it is a poor idea to start that close to the published max. However this is a match chamber and barrel, and in such cases I do not think 2 grains below is even close to pushing it. This is just my theory. With a factory Remington, or Winchester I would start in the middle of the low to high charge to start. After all, the way I look at it is if I buy a 308 I want 308 velocities, not the velocity of a 30-30. I always fire the first round and check the brass for any indication of pressure. After that I more or less follow Dan Newberry's OCW method.

BTW 10% below max is below the minimum charge.
 
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