COAL 338 Lapua

[Canuck257]

Rifle is a TRG-S with 26" factory barrel. Bullet is the Hornady 250 grain HPBT Match moly coated (by me). Powder is 99 grains H1000. Primer is Federal 215. Brass is Lapua. Round is loaded to "touch" the rifling, determined using a chamber length case and a comparator. This combination gives consistent sub MOA accuracy at a velocity of 3140 fps measured on a Pact Professional chronograph 18 feet from the muzzle with NO pressure signs at all. Hodgdon list a book maximum for H1000/250 non-moly bullet of 98.0 grains.

Is this, as I believe, a velocity higher than the norm? And, if it is, why no pressure signs?

Also, as I am about to start testing at different bullet jump intervals I would like to know what you guys have found to be the ideal jump in your rifles?

 

[mdmp5]

Re: COAL 338 Lapua

3140 is a high velocity for the 250, but 99 gr is also on the high end. Not super charged, but high. With 97 gr of H1000, I get about 2950-2970. My ideal jump is 0.025", which is the mag length of my TRG42. I tried loading a few to the lands and single fed them, but the rifle shot better with them loaded mag length, so that is what I stick with. The moly may be contributing to the higher velocity. I would back the charge off and see if it shoots any tighter. You may be sacrificing precision for velocity. Once you get a really nice tight grouping, then start backing off the lands 0.01" at a time.

 

[aaronraby1]

Re: COAL 338 Lapua

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: palmik</div><div class="ubbcode-body">3140 is a high velocity for the 250, but 99 gr is also on the high end. Not super charged, but high. With 97 gr of H1000, I get about 2950-2970. My ideal jump is 0.025", which is the mag length of my TRG42. I tried loading a few to the lands and single fed them, but the rifle shot better with them loaded mag length, so that is what I stick with. The moly may be contributing to the higher velocity. I would back the charge off and see if it shoots any tighter. You may be sacrificing precision for velocity. Once you get a really nice tight grouping, then start backing off the lands 0.01" at a time. </div></div>

so what im getting out of this is that when you find a sweet load, mess with the COAL/bullet seating depth and it could possibly give better results??

i have the remington 700p MLR in .338 lapua. i havent loaded for it yet but i have brass and bullets ready to be loaded. everything i load for i have trimmed and set the COAL to what the manufactures say.

i have been reloading for about a year now and im still learning a lot!

 

[ChrisGarrett]

Re: COAL 338 Lapua

3140 fps is going to burn through your throat at a faster pace, than a 250gr at say 2900-2950 fps. If barrel life isn't a concern, go with the flow.

I always caution to load the 338LM to the distance you intend to shoot and save that throat from premature errosion.

In my TRG-42, I load to 3.670ish", which is the limit of my two magazines.

Chris

 

[DocB]

Re: COAL 338 Lapua

Canuck257,

Moly will allow the use of a little more powder than bare bullets, so I wouldn't worry too much. Until the weather turns warm.

HTH,
DocB

 

[Canuck257]

Re: COAL 338 Lapua

Thanks for all the input guys. I plan to start playing with the COAL as soon as the weather improves just to see what does happen as the "jump" increases. I have not tried the heavier bullets as this barrel has a 12 twist.

I'm not convinced that I will ever have to deal with "hot weather" again, it's -17C at the daily high and it's still dumping snow in my yard quicker than I can plow it.

I'm just in the final stages of bedding this rifle into a Mac. A5 and Arma-Coting all the metal work. When that's finished I plan to put a lot of rounds through this barrel to wear it out then replace it with a longer 10 twist tube with a slightly heavier contour. I'm not sure what make I will replace it with, it will depend on whats available here in Canada???