338 Lapua Ackley Improved Load Help

[SHRTSHTR]

Hi,

I will be converting my 338LM to a Ackley Improved 40 degree shoulder. The barrel is a Lilja, 30" 1-10 Twist, #8 Contour. I think that H1000 or Retumbo are good choices but would like to hear what you gents have to say. Plan on sticking with the 300 smk's.
Need info like, Primers, Charge weight, how far off the lands, etc. Thanks in advance.

Ray

 

[6mm Shooter]

I shoot 110gr of US869 out of mine. 30" Brux and I get 3030fps with 300gr MK. I use Federal Match primers and load the bullets 10thou off the lands.

 

[SHRTSHTR]

Wow, that is very impressive! I doubt that I will achive that out of a Lilja Barrel as they seem to have a tighter bore than most.
My 338 Lapua was getting 2725fps when new. After a couple hundred round, it jumped to 2750fps, 90gn. H1000. I would be happy with these same numbers in the 2900's.

 

[jwp475]

I shoot 110gr of US869 out of mine. 30" Brux and I get 3030fps with 300gr MK. I use Federal Match primers and load the bullets 10thou off the lands.

How do you like the 40 degree shoulder?

 

[jmden]

I shoot 110gr of US869 out of mine. 30" Brux and I get 3030fps with 300gr MK. I use Federal Match primers and load the bullets 10thou off the lands.

Hi 6mm,

How many loads do you figure you'll get out of those cases?

How's the accuracy at longer ranges?

Have you tried that load over a wide range of temps? Curious how 869 would do in that chambering with that bullet over a wider range of temps. My experience with it in the 300RUM shooting 240's was that it was pretty temp sensitive. But it seems some are getting very good velocities with it. I know 'long ranger' up in Canada ( Alberta Tactical Rifle Supply ) shoots just a bit stiffer load than that and has many, many firings on the same cases.

 

[SHRTSHTR]

jwp475,

Do you have experience with something other than a 40 degree shoulder?

I too am interested in US869. I would like to stick with a powder that temp insensitive, this why I asked about Retumbo and H1000.

 

[RockZ]

I have only shot the 300 SMK's in the fireforming loads and I am using 94 gr Retumbo loaded at 3.710 OAL which is .010 off the lands.
I know alot of people who fireform with the bullet in the lands but this worked out for me as a very accurate usable load. 3 shots in 1/4"at 100yds.

I never shot the 300 SMK's in fireformed brass but am going to do that in the next month or so.
I just ordered 500 of them from Midway and should get them next week.

So far in fireforming, Retumbo showed more accuracy than US869 for my rifle. But I haven't given it a very extensive test yet.

I have a buddy with a 7MMRUM who uses US 869 and it has been the best powder by far in that cartridge. I too am interested in building a 7RUM.

 

[jwp475]

jwp475,

Do you have experience with something other than a 40 degree shoulder?

In my mind it is too steep, I am thinking of an AI with a 35 degree shoulder, thus my question. Does the 40 degre shoulder give you any problems?

 

[6mm Shooter]

My rifle is a single shot so the shoulder does not hinder feeding for me and there is no problems when setting the shoulder back.

As far as brass life I have not had any failures yet but I only have 4 firings on 50 pieces.

 

[superpete]

My rifle is a single shot so the shoulder does not hinder feeding for me and there is no problems when setting the shoulder back.

As far as brass life I have not had any failures yet but I only have 4 firings on 50 pieces.[/QUOTE

ben running 250gr bergers at 3411 32in tube retumbo

 

[JeffVN]

I run either VV570 or RL-33 in my 338 LM Improved (40 degree shoulder - single shot), pushing 300 SMKs, 300 Lapua SC, or 300 Bergers to 3,000 fps w/o pressure. My current lot of brass has right at 12 reloads on it.

Avoid max pressures and anneal, anneal, anneal.

JeffVN

 

[alcesgigas]

Go here: .338 Terminator - AmmoGuide Interactive
I thought I put this info on this site; will now.

My rifle is a "second generation" 338 Terminator + P. Your rifle should perform similar or maybe just a little slower because it isn't a P chamber; maybe slower yet due the Lilja barrel. I say MAYBE, who knows until it's tried.

Hope this helps.

 

[longshotdew]

Hi,

I will be converting my 338LM to a Ackley Improved 40 degree shoulder. The barrel is a Lilja, 30" 1-10 Twist, #8 Contour. I think that H1000 or Retumbo are good choices but would like to hear what you gents have to say. Plan on sticking with the 300 smk's.
Need info like, Primers, Charge weight, how far off the lands, etc. Thanks in advance.

Ray

Any further developments?

 

[longshotdew]

Any further developments?

Mine is a 338 LMAI, built on a rem700 338P action, blueprinted/ trued, larger recoil lug, bolt with bushing and M16 extractor, Lilja 30" 1:9 twist, #7 contour, termamnator break, AICS folding stock with extended mag 3.85", bedded, Jewell trigger 0.4oz.

Very accurate, Retumbo 97.5gr, 285gr Eld-m, CCI 250 Primers, Lapua brass (FF), Mv 2905fps, 0.3" @100m.

Ranged out to 1320m so far, no probs, using Applied Ballistics Mobile and Kestrsal Elite, first round hits.