.338 LM smoked necks

[psinclair]

hey guys, just got back from the range with the .338LM. trying a lot of different loads and everything is shooting well so far.

the last load i shot is 300 gr. scenar with 85 grs. of retumbo. put 5 shots into .6 at 200 meters. the bolt lift was just a touch stiff and the necks were very black, sooty? i havent seen this before. is it because the bullet is seated down into the powder so far? or is the load just too hot?

thanks for the help!!

 

[heikki02003]

Re: .338 LM smoked necks

I've come across this problem before while working up a load.

REMEMBER: Always work up a load starting at 10% below published max.

Both times I got blackened necks the problem was not enough powder in factory chambers. What happens is, without enough pressure in the case, it becomes dificult to expand the necks and make a tight seal between neck and chamber. Your shooting large, heavy brass, in my guess a factory chamber. Without enough bang your not getting a seal and having carbon fouling flowing back between the neck and chamber.

If it is safe to do so with published loads, and stay below max, increase your powder charge. If increasing you powder charge with retumbo up to the published max load does not solve the problem, try another powder. The key here would be to select a faster burning powder than retumbo.

If trying a few different powders up to max does not solve the problem, you might be sizing your case necks to much and creating to much neck tension for your bullet. But my guess is more powder.

Good luck, let us know how it works out.

 

[jasonk]

Re: .338 LM smoked necks

That load shouldn't be anywhere near hot, I know of one member here using 96gr of Retumbo and the 300gr SMK's.

My first thought was the same as 284win's, you need a hotter load, not lighter.

 

[jasonk]

Re: .338 LM smoked necks

Per the Hodgdon website, minimum is 85gr, max is 94gr for the 300gr SMK

 

[MitchAlsup]

Re: .338 LM smoked necks

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 284win</div><div class="ubbcode-body">I've come across this problem before while working up a load.

Both times I got blackened necks the problem was not enough powder in factory chambers. </div></div>

Completely agree.

 

[ChadTRG42]

Re: .338 LM smoked necks

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchAlsup</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 284win</div><div class="ubbcode-body">I've come across this problem before while working up a load.

Both times I got blackened necks the problem was not enough powder in factory chambers. </div></div>

Completely agree. </div></div>
Yelp. Stand on the throttle. Retumbo is a vert slow powder to burn. It doens't like reduced/minimum loads.

 

[psinclair]

Re: .338 LM smoked necks

thanks for the replys,

ill increase the powder charge in 2 grain incs. and see what happens.

ive loaded and shot 95 grns of RL25 with the 250 scenar with no signs of pressure.

its not a factory chamber it was built by GAP.

ill report back on the next go.

 

[Bigwheels]

Re: .338 LM smoked necks

Hmmmmm. I've been using Retumbo for a while, & all my necks are blackened to some degree, always have been. Even when I was hot enough to get hard extraction, & heavily cratered primers. My load now is a 300 WM 26" 1:10" twist shooting 208 A-Max Moly with 77.5gr Retumbo seated to 3.635" COAL @ 2968fps. 78gr. was too hot, so I backed off to 77.5gr. It's a SAMMI chamber.

 

[ChrisGarrett]

Re: .338 LM smoked necks

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bigwheels</div><div class="ubbcode-body">Hmmmmm. I've been using Retumbo for a while, & all my necks are blackened to some degree, always have been. Even when I was hot enough to get hard extraction, & heavily cratered primers. My load now is a 300 WM 26" 1:10" twist shooting 208 A-Max Moly with 77.5gr Retumbo seated to 3.635" COAL @ 2968fps. 78gr. was too hot, so I backed off to 77.5gr. It's a SAMMI chamber. </div></div>

You also might want to let the necks grow a little longer. If you're always trimming to what...2.712"-14", you might just experiment with some growth and see if that doesn't make a better seal, but the OP's issue seems to be a lack of pressure causing those X, Y or Z length necks to seal off in the throat of the weapon.

Chris

 

[nolo263]

Re: .338 LM smoked necks

My buddy is loading 96.6 grains of Retumbo for the 300 grain smk. You are way to low on powder..

 

[Country]

Re: .338 LM smoked necks

What can happen is the powder is so slow that the bullet is pushed out by a column of unburnt powder before enough chamber pressure is developed to expand the case necks to seal properly.
A little bit of gas gets past the necks .
If you read Hogdons descriptions of its powders usage. I feel that Retumbo is not the best choice for the 338 LM. Try a slightly faster powder.

 

[Bigwheels]

Re: .338 LM smoked necks

I love this place. I let my brass grow a little, & my necks are getting cleaner already. Good Call ChrisGarrett. Thanks.

 

[psinclair]

Re: .338 LM smoked necks

hey everyone thanks for responding. problem solved.. added more powder! acually about 10 grains more. no more smoked necks and still under pressure. 96 grains of retumbo gave 2800+fps with the 300 grain scenar.

 

[Country]

Re: .338 LM smoked necks

Thats good its usually about pressure and necks not sealing properly.
Make sure you clean the necks up with fine steel wool before you reload.

 

[btm_54]

Re: .338 LM smoked necks

What primers are you using?

 

[psinclair]

Re: .338 LM smoked necks

federal 215 magnum match.

 

[esromvre]

Re: .338 LM smoked necks

Well

I got to say this isn't a waisted day I have learned something.

 

[Country]

Re: .338 LM smoked necks

I agree that the federal magnum match should work fine .

 

[btm_54]

Re: .338 LM smoked necks

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pgs</div><div class="ubbcode-body">federal 215 magnum match. </div></div>
I use them they are good.

 

[esromvre]

Re: .338 LM smoked necks

what primers are working for the lapua other than the 215m. cant find any. need like 3 to 5000 if anyone knows where. otherwise gata change my load