OP,

I bought a Montana Rifle Company Seven Continents Rifle in .338 Lapua with Nilgai in mind and have been happy with it. The MRC is light as .338 Lapuas go, right at 10# with a Nightforce 2.5-10x42, which is light enough to use like a traditional hunting rifle, yet heavy enough to effectively soak up recoil. Their muzzle brake is very effective. A very nice load is the 225 grain Barnes TTSX at 3080 fps and the rifle is actually fun to shoot with that load. While the bc is lower than match bullets, the 225 TTSX running that fast only needs 25 - 27 MOA at 1,000 fwiw. Note that correction is less than most 6.5 Creedmoor loads with the 143 ELD.

The recoil is very tolerable and I do not like heavy recoiling rifles. .338 Win Mags typically are in 7 - 8# rifles, do not have decent brakes or no brake at all and the few I tried were rather unpleasant to shoot. .338 RUM, .33 Nosler, or .340 Weatherby would be the others to consider in my view. The .338 RUM is easy to make run well and a trued up R700 can be put together for a reasonable price. However, brass and ammo availability can be seasonal only for the RUM. The .338 Lapua has the best ammo options at this point and Lapua brass is always available, which is why I went with the .338 Lapua.

The only thing I do not care for on my MRC is the 26” barrel, which likely will be chopped back to 24” plus the brake.

For a .375, look at the .375 Ruger, which is gaining ground on the H&H.

another vote for .338 Lapua, I shoot / own 3 Lapua (SAKO TRG-42 and 2 Cadex CDX-33 )

recoil is non issue if you put a brake on it

Can you tell me more about this caliber? 30-06 parent case? Velocity? Custom dies only?

270 parent case (longer neck than 30-06) necked up to 338 with shoulder pushed forward and improved to 40 degrees.

H20 capacity of 77-79 gr depending on brand of brass. Think 338-06ai with a couple extra grains of powder.

My load is a Rocky Mountain ULD 250 gr — 58 gr of Varget gives me 2700 on the nose. Most guys are getting 2800+ with the 250 Berger and R17 or Win 760

Lots of info on the Sherman line of wildcats on longrangehunting.com and snipers hide.

270 case with fire forming load on left. Fully formed case on right

Interesting. My buddy just dropped a couple rifles off with Tony today and he (Tony) mentioned this cartridge to him. I told my buddy I had literally just read about this an hour ago from this post. Seems there is some good horsepower here. Tony didnt mention why this was a pain in the rear, but he did mention that it was. Is there any particular reason why so? Can the dies be purchased off the shelf?

Ha! The chambering wasn’t any different than anything else. Rented reamer from Rich Sherman. Who sells the dies on his site.

But.... I had the hairbrained scheme of converting my old 1980s tang safety ruger originally chambered in 270.

One of the drawbacks of the ruger action is the limitations it puts on OAL due to the short (3.40”) mag well. To allow a longer OAL to feed, I lengthened my action posteriorly with a Wyatt’s cut (which included milling away the center floor plate screw). I fabricated an extended mag box from two factory boxes spliced/welded together. The bolt stop was moved posteriorly about 0.25” by tapping/drilling a new retaining screw hole and the window for the stop was enlarged. I am now able to feed rounds up to 3.600.




I wanted to install a pic rail but those actions are investment cast steel and HARD! Tony broke multiple bits trying to drill and tap the receiver. We ultimately bailed on the rail.

You're onto something here, Red. Will the loaded round fit a Tikka AI mag with your bottom metal?

Beautiful rifle. What was the blank and contour on that? #5 Bartelin?

Do you think it would be an easier install on say a standard Savage or Remington or Tikka action?

My OAL @ 0.015” off the lands with that bullet is 3.530. I think the OAL with a 250 Berger is like 3.575. Max you can get on a tikka with our DBM is 3.50 so you’d have to give up a little on case capacity or run a highly compresssed load. At 58 gr Varget I was 102% filled but with a drop tube it did pack down and leave a little room

Rich Sherman also has a line of short mag cartridges. The 338 Sherman Short Mag is a tough faster than the long action version and the OAL isn’t a concern

Charlie , you’d have no concerns with savage or Rem as long as you can have a mag box of 3.6 — tikka as above


Build Specifics
* Action: Ruger M77 tang safety
* Caliber: 338 Sherman (LA)
* Original wood stock (refinished)
* Pillar and full length bedded
* Benchmark light palma 1:9.4 finished at 24”
* APA Little Bastard brake
* Factory trigger reworked
* Cerakote midnight blue

I bet a shorter hunting bullet like a 200 Accubond would work fine if I loaded to max mag length. Have you tried any light bullets?

ITRDM, for deep penetration on the nilgai you’d might want to consider a mono like the 185 or 220 Barnes TTSX — you could push those hard at 2900 (210 gr) and over 3000 (185 gr). Also a 225 or 250 Swift A Frame. Those and the Accubonds are a lot shorter and OAL wouldn’t be an issue.

Only other bullets I shot were 225 sst for fire forming. It shot those pretty dang good too.

Thank you for all the info. That's some good shooting.

I think I am going to order a 338 blank now. lol Thanks for the post Red. One of the few things that piques my interest these days.

let me know if you guys have any other questions. This was my first wildcat and it was a bit of a learning curve but a really fun project.

I will say that this thing is an absolute joy to shoot. Maybe my favorite. With the break, recoil is more of a shove than a jolt and close to magnum performance in a standard long action case with less powder.

Something is not making sense with those numbers within any sane pressure limits.

58 grains of powder at 102% capacity is virtually identical to a .338-06.

The .338 Win Mag pushes a 210 TTSX at 2900 at the top end for that cartridge using 10 grains more of powder (using your 58 gr of Varget vs. 68 - 70 for the .338 Win Mag.)

Has anyone actually submitted some loads for real pressure testing?

Where he will be hunting in South Texas, temps and the 90's are common even in winter and hitting 100+ in March. I was shooting culls two weeks ago in a T-shirt with temps over 90 in early January.

Pushing a case to the ragged edge is not safe and at a minimum a way to lock up a bolt in hot weather.

For more speed move to a bigger case rather than pushing high pressures in a small case.

It is far safer to load a bigger .338 case with a lighter load for the same velocity or even higher.

My buddy was running a 7 rem mag at the same speed as my 7 saum using at 12 grains more powder. I guess that's what they mean by case efficiency.

58 grains of powder is the same as a .338-06, which is not capable of 2900 fps with a 210 TTSX, unless perhaps is a longer barrel, say 26" - 28", which is not handy in the brush.

Hard to see what is different or magic about the Sherman compared to a .338-06 other than it is AI'd, which might add a few grains of capacity at most.

That velocity with the 210 is looking like a flashing warning light to me, especially for hunting in a very hot environment.

I’m not aware of anyone who has done any real pressure test. And yes, your point is well taken. This is a hot load. I don’t have my QL numbers on my phone for Varget, but the theoretical pressures were right around 65k IIRC. Brass has held up and not shown any pressure signs at that charge. Load was worked up at 100F.

RS,

what is the barrel length?

And just to keep things straight, the .338-06 is a very good cartridge. My only concern is pushing the limit to the very edge of pressure limits, which sometimes might be acceptable in a competition setting, but rarely prudent in field conditions.

eta - I just pulled the Barnes manual off the shelf to look at .338-06 load data, and they also list data for the .338 Scovill, which is the .338-06 AI. They are topping out around 2800 with a 24” barrel. So maybe with 2” - 3” extra barrel length and a “hot” load 2900 is within reach, but it is pushing the outer limits for the case size.

Nice shooting RS.

To clarify and for what it’s worth, the numbers I threw out for the 210 etc were just guesstimates. I haven’t shot any of those or ran them thru QL. Only load dev I did was fireforming with 225 sst using middle of the road charge for 338-06 and then shot for groups/OCW with ROcky Mountain 250 over both mangetospeed and LabRadar starting low and going slow with Varget and RL-16 using QL as a reference

The RL-16 data correlated with what I found with Varget — No pressure signs at theoretical max of around 65k and had close to predicted velocity of 2650-2700.

24” barrel.

The pic above is QL table for RL-16.

Red has nothing to prove. There is no reason. The only reason he published data is because I asked him to.

As an example look up factory loads in 6.5 creed vs 260. 260 has a lot more case capacity but factory loads are slower than in the creed.

Case efficiency is key and I think red is onto something.

Once I started playing with QL, I was astonished at the effect that case capacity and seating depth has on pressures. Data (pressure, velocity, etc) predicted by QL for the 338-06 is significantly different that the 338 Sherman (extrapolating using the .338-270 HGT as the case).

Jeffbird brought up several good points on what constitutes a safe load and reasons not to be on the ragged edge.

Just look at the case vs 338-06. It looks apparently different. There is an efficiency difference there like a 223 ackley can almost duplicate 22-250 with just a shoulder bump. 284 shehane is another cartridge that, just from a shoulder bump turns into a completely different animal. Again, 6.5 creed is the best consumer example off this.