375 Snipe Tac...Barrel and Bullet tests

[Augustus]

OK, I intend to start with US869 and H50BMG, Ill just start low and build up. I dont know if I will be the first to test these or not. I do know that Barney is building another rifle for another party at this time, it may be that he will get his before I do. I cant wait to try these things, if the round comes anywhere close to the projected numbers I will be a little surprised and a lot impressed. This is totally experimental and the twist rate, # of grooves, throating and dememsions of the bore are being done using educated guesses. Anyway if it goes through the target sideways we will know we didnt get something right.

 

[Black Diamond 408]

I just came back from testing the new style 350gn SMK.

Seated .015 off the lands.
Retumbo powder
Fed 215M

140grns ave fps 3149 ES 8

142grns ave fps 3211 ES 9

I fired the 140grn loads at my 700 yard plate, 8.75moa added...all three shots landed on steel, spread was about 4" The cases extracted easy, no marks on case head at all.

The 142grn load was .5 moa less, all shots landed on steel as well. The cases extracted easy, just a bit of shiney mark on case head. Temp was in the low 80's I used .770 for the BC in Exbal, came out perfect. This is one big Thumper!

700 yard steel target

Cowboy-Dave

 

[Fiftydriver]

Dave,

Sounds like your new 375 is working well for you.

Why did you move the shoulder forward compared to your 338 Sniper Tac?

Your loads look right where they should be comparing them to the tests I have run on my 375. I am getting 3250 with 143 gr of Retumbo and 3300 fps with 146 gr.

Like you are seeing, they are very friendly in warmer temps compared to the 338 siblings. Just wish there were more bullets available but the 350 gr is good enough to get the rifles shooting well.

I am not a fan of the solids, certainly they are ballistically impressive but to bore sensitive and not usible for big game hunting. Not even legal to use here in Montana on big game and I beleive there are other western states that require an expanding bullet for big game. With enough interest maybe we will get some more bullet options with a lead core bullet design.

Ya need to double your range and see how your lightweight rig runs for you.

That is a unique gong design. Good use of scrap metal however!!! May be trickier to hit at longer ranges though.

Anyway, good looking rifle.

Just curious, why do you not make your own muzzle brake? If you want something that will really tame down your rifle, let me know and the PK brake will make a believer out of you!!! LOL

Take care,

 

[Black Diamond 408]

Kirby,
I normally make my own brakes, but like you know...when your busy its hard to work on your own guns. Yes your PK brake works real well, i did one similar on a 408 several years ago. When i get my CNC Mill up and running i can do more of that type of machining. The Lawton brake will be installed later on a customers rifle, and ill put one of mine on this boomer.

My original 338 snipe tac has the same case profile, when i put some of the taper back into the case i shortened it just a bit, all during the R&D phase, It worked well so i just stayed with it. Either one has plenty of case capacity and if i use the cheytac magazines they will still feed from them, any longer and they wont fit at the shoulder retaining area.

I am surprised the solids shot so good in a 12 twist, they are mostly for shooting vermin or steel at long distances.

I was out looking at my range today, max distance is 700yds, there is a county road right behind my shooting table, if i go across the road i have another 800yds or more, but i have to do some figureing, there is a set of electric lines that crosses my line of sight. Im sure at 1500yds i would be way over them but need to make sure first.

I have lots of 1/2" steel plate, 3'x4' square, but the darn bullets dont want to stop when they hit it. yea i wish the AR400 drops i have were bigger, lots of small pieces.

I think i will stay with the 142grn load, it seems to work good and no real pressure signs.

Have you experimented with different twists?

Dave

 

[Fiftydriver]

I have tested the 1-10 and 1-12 from Lilja and Krieger. With the 350 gr SMK I have never really seen any NEED for the 1-10 but use it more then anything simply for the reason I am hoping soon we will have some very long 370-380 gr aluminum tipped lead core bullets to play with!!!

At the velocities we are using the newly designed 350 gr SMK has no issued in either twist from what I can see so far as far as overspinning them.

I did take some of my last TTI cases and form them up. As you know they will take alot more pressure then the Jamison hulls. Got the 350 gr SMK up to 3445 fps with very practical base life, 5 firings per case is where I stopped testing.

I had several of the early SMK design come apart at these speeds in the 1-10. I have also had a couple instances where the new design has mysterious failure to impact issues at 1500 yards. I can only come to the conclusion that this was due to a weakening bond between the core and jacket. There was no visable blue-grey puff by my spotters and bystandards but they did not make it to the target or land close enough to make it obvious where they hit??????

At 3300-3350 fps I have never had any problems at all in the 1-10. Like you, I keep things in this level to keep pressures lower, still plenty of punch!!!

I had a couple custom contoured barrels made for me by Dan Lilja, They are actually lighter then a #8 contour barrel with a 1.250" shank diameter. They will finish up at 32" in 338 and 30" in 375. I suspect they will get me down to under 16 lbs with a conventional A-5 stock and BAT Model M receiver. Have to just find time to get away from customers projects and spend some time on a couple of my personal ones.

That will likely not happen until well after big game season!!!

Take care, keep us posted. For extreme range steel slappin, those solids sure look like the trick!!!!

 

[remingtonman_25_06]

WOW! Nice rifle!! That cartridge is just insane. A 260g AB at 3700 is just plain nuts. And those solids are CRAZY looking. I need to start saving so I can have something like that. I can shoot as far as the eye can see out here in the desert...Would make an awesome LR coyote gun with those missile's LOL.

 

[Akkill]

super good thread, super good rifle and super good experts, why don't you guys try the .375 300 grains accubond, it should be a good hunting bullet

 

[Fiftydriver]

Can you get the 300 gr Accubond. I think it would be a great, light bullet option, in my opinion a better choice then the 260 as it will make this huge capacity burn more efficently but I have not seen anywhere where it is in stock and available.

 

[WyoRanchHand]

The 300 gr Accubonds won't be available until the end of the year.

 

[Black Diamond 408]

super good thread, super good rifle and super good experts, why don't you guys try the .375 300 grains accubond, it should be a good hunting bullet

I will be testing them when available.

Dave

 

[Augustus]

For those interested in the solid projectiles; things are really starting to click now. There is a bullet maker here in the states that is making a solid for .224, .338, .375, and possibly .408. The .375 has two versions right now. One will be the shorter version and will stabilize in a 11.5 twist. The other will require an 8 twist. I should be testing the ones from Germany and these made in the states within 3-4 wks. The BC of the German and fast twist domestic bullets should be off the charts. There is a lot of unknowns at this point but i am very excited. Let the games begin!!!!!

 

[Augustus]

Oh. I would like to say I have no dog in this hunt except i like to shoot and push the limits. I have nothing to gain from this project and the only thing I will lose if these things fall on their face is the cost of the projos and an 8 twist barrel fron Lawton.

 

[lazylabs]

Who is making them and what is the cost?

 

[Augustus]

Lazylabs, the Viking is made in Germany, this is the wierd one that is pionted on both ends. The cost on the 300 I have is a little over two dollars each. I dont think the gentleman that is making the domestic bullets wants to come out of the closet until they have been tested, he is sending me a few of the ones made for the 8 twist barrel and we will see if they need to be tweaked. He seems to be very interested in developing a superior system moreso than simply selling bullets. He has told me they will be cheaper than the German bullet. Also he is very close to testing a new case to push the new pills in. There is work being done on the propellant and he is hoping to have the entire system at the SHOT SHOW. There are a few more people getting close to testing all of these banded projectiles so there should be a lot of feedback in the next couple of months.