338 LM 250 SMK Load Results

[.375Mojave]

Started some initial testing on my Savage 110 HS in 338 LM.

Started at 88gr of Retumbo with 250 gr SMK's doing my barrel break in for about 25 rounds. Started with 3 shot groups vs ladder testing just to get some trigger time, the Accutrigger is a little different but seems like a good system so far.

Shot a series of 3 shot groups from 90gr through 97 gr, no significant indications of pressure and will head back out with some rounds through 98.5 gr. Didn't set up my chronograph yet so I dont know what kind of velocities I was getting.

Thus far my best groups were in the 92.5 to 93.5 gr load range, getting .75 MOA groups at 200 yards. Wind started to kick up pretty bad toward the end and may have been a contributing factor to the groups loosening up as I got past 95 gr.

Has anyone else done any load development with 250 gr SMK bullets and found the best loads at these charge levels? FYI hit 100% case capacity at about 96 gr and 97 was just slightly compressed in the new unfired Lapua brass.

I will push the loads in both unfired brass as well as my once-fired with neck sizing only. I am looking for pressure to drop a bit as I am getting about .0025 in expansion near the shoulder from fire forming and am neck sizing only. Hoping to find another swwet spot closer to max loading around 98+gr. We will see.

Just wanted to hear if anyone had an optimum accuracy load with Retumbo and 250 SMK's in their 338 LM.

Thanks.

 

[ChrisGarrett]

Re: 338 LM 250 SMK Load Results

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: .375Mojave</div><div class="ubbcode-body">Started some initial testing on my Savage 110 HS in 338 LM.

Started at 88gr of Retumbo with 250 gr SMK's doing my barrel break in for about 25 rounds. Started with 3 shot groups vs ladder testing just to get some trigger time, the Accutrigger is a little different but seems like a good system so far.

Shot a series of 3 shot groups from 90gr through 97 gr, no significant indications of pressure and will head back out with some rounds through 98.5 gr. Didn't set up my chronograph yet so I dont know what kind of velocities I was getting.

Thus far my best groups were in the 92.5 to 93.5 gr load range, getting .75 MOA groups at 200 yards. Wind started to kick up pretty bad toward the end and may have been a contributing factor to the groups loosening up as I got past 95 gr.

Has anyone else done any load development with 250 gr SMK bullets and found the best loads at these charge levels? FYI hit 100% case capacity at about 96 gr and 97 was just slightly compressed in the new unfired Lapua brass.

I will push the loads in both unfired brass as well as my once-fired with neck sizing only. I am looking for pressure to drop a bit as I am getting about .0025 in expansion near the shoulder from fire forming and am neck sizing only. Hoping to find another swwet spot closer to max loading around 98+gr. We will see.

Just wanted to hear if anyone had an optimum accuracy load with Retumbo and 250 SMK's in their 338 LM.

Thanks. </div></div>

Retumbo will work, but it might be on the slower side of things and works well with the 300gr heavies.

I shoot exclusively the 250s in my 1:12" TRG and my 'go-to' load is ~88grs of H-4831sc and VV-165. I also like VV-170 and H-1000. I have some RL-25, but haven't used it.

The load is proven for me, out to 1k, as that's as far as I can shoot here in SoFla.

With the 250s, try some of the slightly faster magnum powders.

Chris

 

[.375Mojave]

Re: 338 LM 250 SMK Load Results

Thanks

I have a lot of Retumbo from loading my 375 Chey Tac so I gave it a whirl and Hodgdon had a load in the chart.

I think I will pick up some H1000 since it is also a good choice on 300gr bullets from what I read.

Thanks for the feedback.

 

[sinister]

Re: 338 LM 250 SMK Load Results

Thales - Australian Defense Industries (ADI) makes Varget (AR2208), Retumbo (AR2225), and H-1000 (AR2217). Hodgdon imports it and re-labels for the US market.

Their published load data info is at http://www.adi-powders.com.au/handloaders-guide/rifle.asp

 

[.375Mojave]

Re: 338 LM 250 SMK Load Results

Went out today and ran some more Retumbo loads with the 250 SMK's. I ran Retumbo to a max load as well as some RL 22.

The Retumbo maxed out at 98gr pushing 3193 fps avg with about 12 fps spread on velocities. Bolt and ejection still smooth but just started to see the ejector spot at 97.5 so I will back it down to 97 as a max for my Savage 110. It was grouping .6 MOA until the wind started to push 10 mph and I started to get some lateral spread at that point. 97 gr yeilds about 3150 fps according to my chrono so at least I have a useable load.

The Alliant RL22 I took up to 89.8gr which is book max with no pressure signs getting 3035 fps. I will creep up another couple grains and find the wall. Velocity spreads were similar to Retumbo 12 to 14fps deviation. Great groups, sub 1/2 MOA.

All shooting was at 240 yds as this was a convenient setup in the spot in the desert North of Vegas. I am using a Lead Sled since I want to know what the rifle will do, not me, and because running 50 rounds through this beast naked will tend to leave you sore. Getting 1" groups from the RL22 and 1.375" groups out of the Retumbo at 240.

I have to say that this is my first Savage and I am about 125 rounds in and this gun is a shooter.

 

[.375Mojave]

Re: 338 LM 250 SMK Load Results

Post Script:

Checking my Speer manual it is pretty clear that my Chronograph is reading high unless I am defying physics with my velocities.

98 gr of Retumbo in my Savage 110 hit a high reading of 3203 fps with an average of 3193 fps according to my Chrony, which appears to be impossible.

Any ideas on how to re-calibrate a chronograph? I will post to "Exterior Ballistics" for suggestions there.

 

[X-fan]

Re: 338 LM 250 SMK Load Results

There is nothing wrong with your chronograph...it is just sensors and a clock...dead simple and reliable. The only way you can hurt it would be to change the distance between the sensors (not easy).

You probably have the muzzle too close to the muzzle on a marginal (wiggly) tripod. If the Chronograph wiggles around from muzzle blast at all it wont read properly. Make sure the setup is tightened down and wiggle proof. If it doesn't work at the usual 14 feet try 20.

Also check your lighting.
If you are in bright sunlight create some shade so both sensors are evenly lit...Never one different from the other.
Shade is always better than direct sun.

Hope that helps

 

[.375Mojave]

Re: 338 LM 250 SMK Load Results

Thanks for the tip. I will move it a little further out. I was at a recommended 10' and figured that, even though it is a pretty hairy round, with the muzzle brake on this rifle it would cut the forward blast so nothing extraordinary would be required.

I did put this on the Exterior Ballistics forum and I had noted that the unit was not perfectly flat (fully opened) by a couple degrees. I tried to force it but it would not open any more. I am going to take a look at that and see if there is a catch or something I was missing.

Thanks,