338 Sherman Build (This Is My Boomstick!)

[benchracer]

Had this build in the works for a long time. My finished rifle finally arrived at my FFL a couple of days ago...



Rifle specs:

LH Ruger 77 MkII
Factory Ruger Laminate Stock
Krieger #4 contour, 9.3" twist, 26" barrel
4 port Lil' Beast muzzle brake
Murphy Precision picatinny rail
Metal finished in Black Graphite Cerakote
SWFA 3-15x42 FFP MIL/MIL
Warne rings

Shawn Thomason of Diamond T Rifles did an outstanding job of putting it all together for me. Attention to detail and pride of workmanship are evident in the finished product. I am very impressed with his work!

 

[Idaho Trecker]

Looks great! I'll second that on Shawn' s work! I've had him do my 270 Sherman, 270 SS, 6 dasher and 338 edge and all shoot exceptional! I wish I had the funds to do a 338 Sherman or SS. That should be a real hammer. Can't wait to see some groups.

 

[benchracer]

This is my first experience with a wildcat cartridge of any kind, so there has already been something of a learning curve for me. Loading for the Sherman wildcats is not difficult, but it is different. I will detail what I have learned as this thread progresses.

In the interest of exploring the capabilities of the 338 Sherman, I intend to do a lot of load work with this rifle. Rich Sherman designed this cartridge around 250 grain bullets, specifically, the Berger 250 Elite Hunter. I will be using Hornady 250 HPBT's to fire form my initial batch of brass, to be followed by testing with Berger 250 EH and Cutting Edge 252 MTH's. I will also be testing Cutting Edge MTH's in 225 and 200 grain weights, along with Hornady 225 and 200 SST's.

I currently have 50 rounds each of PRVI and NORMA brass loaded with fire forming loads. I also plan to fire form and test RWS brass at a later time.

During the planning phase for this build, Rich and I had discussed use of RL-26 with the 250's. However, the initial results with Rich's 338 were not what we had hoped for. He had much better luck with RL-17 and Hybrid 100V. After discussing the matter, it seemed likely that the disappointing initial results with RL-26 may be caused by an ignition problem. With that in mind, I will give RL-26 another go, using different brands of mag primers, in hopes of getting the results we were hoping for. Otherwise, RL-17 and Hybrid 100 V will be tested with the full spectrum of the bullets listed above.

I will report back as I have results...

 

[benchracer]

Looks great! I'll second that on Shawn' s work! I've had him do my 270 Sherman, 270 SS, 6 dasher and 338 edge and all shoot exceptional! I wish I had the funds to do a 338 Sherman or SS. That should be a real hammer. Can't wait to see some groups.

I should mention that Rich did the leg work in helping me find a good smith to tackle the project. I really appreciate his efforts in helping to make this happen.

Sounds like Shawn has built some fine rifles for you! I do expect the 338 Sherman to be quite a hammer. After seeing Rich's initial results, I am anxious to see what my rifle will do, though it may be a week or two before I get down to any serious accuracy work.

 

[Idaho Trecker]

It's a journey you will enjoy with the new round. I've never tried cutting edge bullets (cost and inflated bc' s) as for the 250 Berger it has the bc and weight but I've had to many Berger fails. I think rich is on the right track with the accubond for his rig. I'll be interested to see if mag primers solve the Rl26 problem. I personally think the bore size is why the 100v burn rate has worked best. My 300 SS with 225 eld m and rl26 are nearly maxed out on capacity and pressure.

 

[TXAoudadKlr]

What's the expected performance of this round?

 

[elkaholic]

What's the expected performance of this round?

Mine has reached 2860' with the 250's, which was a pretty stiff load but I shoot them at 2810 regularly with my 24" barrel. It is super accurate and should be a real hammer at close to 4600 ft. lbs........Rich

 

[elkaholic]

VERY nice Brad! I am glad you are ready to get shooting and hope to see some nice results. I am interested to see how much difference the 26" barrel makes and also how the mag primers work with RL26.....Rich

 

[gj]

Had this build in the works for a long time. My finished rifle finally arrived at my FFL a couple of days ago...

View attachment 78257 View attachment 78258

Rifle specs:

LH Ruger 77 MkII
Factory Ruger Laminate Stock
Krieger #4 contour, 9.3" twist, 26" barrel
4 port Lil' Beast muzzle brake
Murphy Precision picatinny rail
Metal finished in Black Graphite Cerakote
SWFA 3-15x42 FFP MIL/MIL
Warne rings

Shawn Thomason of Diamond T Rifles did an outstanding job of putting it all together for me. Attention to detail and pride of workmanship are evident in the finished product. I am very impressed with his work!

Nice,,,, but how well dose it group 5 shots ?

 

[elkaholic]

Well, here are 5 shots at 400 yards. The wind let up the last shot.

 

[NEMTHunter]

Very nice benchracer. Always nice to see a Ruger build!

 

[elkaholic]

I will use the accubond if I shoot the 200's but will likely use the Berger 250 as well.....Rich

 

[mountainman56]

Had this build in the works for a long time. My finished rifle finally arrived at my FFL a couple of days ago...

View attachment 78257 View attachment 78258

Rifle specs:

LH Ruger 77 MkII
Factory Ruger Laminate Stock
Krieger #4 contour, 9.3" twist, 26" barrel
4 port Lil' Beast muzzle brake
Murphy Precision picatinny rail
Metal finished in Black Graphite Cerakote
SWFA 3-15x42 FFP MIL/MIL
Warne rings

Shawn Thomason of Diamond T Rifles did an outstanding job of putting it all together for me. Attention to detail and pride of workmanship are evident in the finished product. I am very impressed with his work!

 

[mountainman56]

Very nice indeed! You're going to have a lot of fun with that.