My 338 Sherman Shortmag

[bdlesh]

you bet. let me know when I can help

You will be the first to know!

 

[Akmtnrunner]

You cant go wrong with the ss if 2800-2860' makes you perfectly happy! Just throwing out options since you will have the length. The wsm would also fit but it isnt as efficient and there is no quality brass to compare to ADG in the ss or max. Lots of options

I mean, would a 300 wsm chamber be better to use to make into a 338 SS, than another factory chamber? I have the choice of what to start with so I'd like to know which is easiest to ream the SS into, and if it is a simple matter of reaming.

 

[elkaholic]

I mean, would a 300 wsm chamber be better to use to make into a 338 SS, than another factory chamber? I have the choice of what to start with so I'd like to know which is easiest to ream the SS into, and if it is a simple matter of reaming.

Gotcha! It would be better for a 300 SS for sure but Im not really any kind of authority on whether or not boring a barrel out is the way to go? The chamber length of the 300 wsm is definitely closer to the ss although about . 140" longer

 

[WiscGunner]

I would call Patriot Vallley Arms as they make pre-fit barrels for Tikka's. Likely a better route than boring a factory barrel and rechambering it. They don't have Sherman chamberings listed for the Tikka barrel but that is likely due to web development as they do have them listed for other barrels.

https://patriotvalleyarms.com/tikka-prefit-barrel-barrel-nut/

 

[ramrod79]

Finally got some finishing touches on my 338ss completed. I'm running load work up with ADG & some Norma brass for a comparison. All were fireformed with 215m, 55grs of RL17 & 285 eldm's @ 3.082" coal. Sized & bumped .003" w/.420 guage trimmed to 1.930" w/ .360 bushing.

First round of load work up running Varget & RL17.

#1. ADG Brass- 240 Bulldozer, Varget, 215m
59 grs 2754'- 59.5grs 2783'- 60grs 2812'- 60.5grs 2836'- 61grs 2842'- 61.5grs 2877' 62grs 2902'
Got a slight swipe on the case @ 62 grains with the primers starting to flatten but no stiff bolt lift & easy extraction.

#2. Norma Brass- 240 Bulldozer, RL17, 215m
62grs 2806'- 62.5grs 2838'- 63grs 2855'- 63.5grs 2888'- 64grs 2906'- 64.5grs 0? 65grs 2956'.
Did not pressure out yet with RL17! Wow, but great velocity! I used a 4" drop tube to settle the last two powder charges. Crunching kernels, quite compressed but didn't push the bullet out at all. Will try to fit 66grs in next time out to top 3000' with the 240 Bldzr'.

#3 ADG Brass- 285 ELDM, RL17, 215m
58grs 2530'- 58.5grs 2569'- 59grs 2584'- 59.5grs 2609'- 60grs 2635'- 60.5grs 2624'- 61grs 2661'- 61.5grs 2676'- 62grs 2693'-
Primers starting to get flat @ 61.5 & 62 but no swipe, no bolt lift at all. Will load another grain, grain & a half to pressure out next time.

#4. Norma Brass- 230 ELDM, RL17, 215m
Ran 4 at 64 grains for group & three more to 65.5 grains to see if I pressure out with the 230. 2792, 2795, 2795, 2794 @ 64grs RL17. 65.5grs was not max yet at 2892'! Quick note on the 230's. I had these seated out real far & they still were jumping almost 80 thousandths.




View attachment 143606

KMG I just started my load work on 230ELDM today fire forming with 57gr of Varget was 2706ft/sec SD5 ES 13 was about 2 inch groups at 368 yards.Tomorrow I will run to pressure see what we get.ill post my results where I pressure out.

 

[Skimbleshanks]

Just a quick tangent if I may. I own a
338-300WSM. Im shooting the 225 Accubond and get a slight ejector swipe on the brass and flat primers with I believe 61 grains of Varget. Ill check my book tomorrow. Im using nosler brass and im only getting 2750fps with a 28" barrel. I had this rifle built years ago because I thought a modest case size coupled with the mid weight 338 bullets would be an awesome combo. To be honest I'm kinda disappointed with the velocity given the barrel length. I was hoping to be pushing them a bit closer to 3000. I guess my questions are; are you guys just pushing pressure because the brass can handle it? What is the case capacity of the 338ss VS my WSM? Does the case shape make that much of a difference between the Sherman results and my WSM? Is the 225 accubond the limiting factor due to bearing length? I'm hoping I can take advantage of some of this great load data or have a place to start with other load options. Thanks for letting me hijack this for a moment.

 

[ramrod79]

That seems really low in velocity for such a long pipe I'm running a 24inch pipe and with a 250 I was getting that at 60 gr of Varget.
To answer your part of your question yes the case design helps this cartridge work the way it does through efficiency.
I always run my cartridges to pressure just to see where pressure is at plus my top end nodes are usually 1to .5 under pressure.
This ADG brass is really good as well I'm onto 5th firing on my first brass and it's been run hard.
Have you tried any other powders with yours? Being that you have a bit more case capacity and different design maybe N 565 or something along those lines may work better.
I'm sure a Rich or one of the other fellas will chime in help you out.

 

[ramrod79]

There is a good blast on 24hr campfire on your 338wsm seems they are doing a bit better with shorter pipes

 

[codyadams]

Also, the ss is throated properly for the 250 bullet, likely much longer than your wsm. If you throated your wsm to where the bearing surface of the 250 was at the neck shoulder junction, it is very likely that it would outperform these sherman short cartridges with equivalent strength brass. However, you would need to run it single shot or in a long action.

 

[elkaholic]

All good info above! The ss has proven to be a very efficient case , especially noticable in shorter barrels. One thing that you mentioned though about the 225 AB, yes, the bearing surface slows it down. I was barely able to run it past 2900' which wasnt all that much faster than a 250 Berger.

 

[ramrod79]

Well I was able to get out today to try some testing on 230ELDM. I usually do not do load development like this but thought I would give it a try. You will see that my velocities go up from 20-25 ft/sec and I really saw no node. On a good note I did not hit pressure at top charge either.
Shot 7&10 not sure what happened there I shot 5 let gun cool 10 mins shot the other 5. If anyone has any thoughts or input I'd be happy to listen. I'm gonna load up more rounds but go up in .3 increments now as I have to be getting close to max but with no hard bolt lift and primers looking so good maybe I have left than I think.
230s are just off lands now 5 tho. Target was shot at 170 yards.

 

[ramrod79]

So 62.7 slight stick bolt lift and decrease in velocity to 2933 62.9 same thing 2937 didn't shoot the rest. I think I'll start at 61 go up in .3 increments and back off lands to 10 tho see how that plays out usually .5-1 gr below max seems to work. I think that should put me very close to the 2900 mark witch I think is excellent with this little round and a 230.

 

[ramrod79]

Well I was able to get out tonight to do load work started at 60.7 went up in .2 increments. I found this one at 61.4 gr of Varget at 10 off lands for almost 2900ft/sec. This is .75 inch at 200 yards so I'll load a bunch up see how it plays out I hope good as nothing else really showed me promise all the rest shot 1.25" and my 61.6-62 opened way up on me.
If it holds up AB has this at 1min gain at 1000 over the 250 Berger and it's only 200ft/lbs less than the 250 at 1000 yielding 1547ft/lbs.

 

[ramrod79]

Was able to get out this morn run the last 5 brass out over chrono for a final number. 2885 with 230 ELDX @ 61.4 gr varget
SD-2
ES-5
Tonight I'll run out to 800.