416 Barrett vs. 375/408 SOE

[triggerfifty]

I was looking at Barrett's site info on the 416. 3250 fps and a supersonic range of 2500 yards? By my math, that's around a .88 BC bullet. Does anyone know of anyone that has this cat? I'd like to shoot against it side by side known distance or unknown distance against my 375/408. This bullet does 3250 fps also, but has a supersonic range of over 2900 yards at sea level. Measured.

Anyone know anyone?

 

[James Jones]

From what I understand they are using lathe turned bullets to a specific profile , not sure of the weight but a BC in that range could be possible.
But I honestly don't think the 416Barret has a hand up on the 408ChyTac or hell even Kirbys 338Allen.

 

[Black Diamond 408]

Barret is using a turned bullet @ 400grns.

I am currently working on the almost same thing but in the .408cal... I feel the 408 bullets avalible now would make this a REAL long range round. 408 bullets have BC's in the high 900's and more stuff on the way, hoping for 450gr ULD type bullet from Richard. The only draw back to the whole thing is you have to use a 50cal action of some sort. With the 408 case you at least can build a carry rifle under 16#. I love my 338 snipe-tac, easy to carry and recoil is not bad. Groups are outstanding for this shoulder cannon.

The prototype action blank is on the way, it is a simple full bolt style WBY type only i'm using two locking lugs on this project. I have designed a large rem 700 type that will take this short BMG case as well. It will be a while before they are ready, the Wire EDM guy is working on them as we speak. I dont know how light a person can get one of these, you can get a 408 type well under 16#, with the larger bbl of the 50cal case and action, maybe 22# time will tell.

What 375 cal bullets are you using to get your stats? My original design was to use a 375cal bullet in the 408 case, i couldnt find one with a high bc. At least 4 years ago i couldn't.

-Boys and their toys

 

[triggerfifty]

Morning, i've seen those 400 gr. bullets. They appear to be a cross between Barnes and the Lost River design, with no particular cross breeding between the two. The LRBT design is patent protected (can't blame them) and the Barnes material is wrong. Combined with that bullet material and the velocities, you have some serious wear issues going on. As you know, brass solids are highly abrasive. The brass is too big, making the need for a too big reciever, but that's not exterior ballistics. The .50 case could drive the 419 .408 bullet faster, but perhaps not as efficiently because of powder / barrel length / efficiency issues.

Right now the 375/408 will smoke this 416 Barrett in a smaller case, with a far superior designed bullet. Is your 338 rifle based on the .408 case? Have you tried the new US869 powders in that?

The .375 bullet I use is from Lost River Ballistics. I know, that'll raise some fur, but they make the best solid long range bullet out there. I've shot them all, alot, in testing against the .408 to ranges of well past 2000 yards. Jacketed bullets don't have the BC values to push supersonic to 2000 with having a short danger space.

Won't say the meausured and determined BC directly. But let me put it this way, the launch velocity is 3265 fps, and has a supersonic range of 2930 yards at standard air conditions (APG BRL standards). If you have a back calculating program, you can do the BC check on that.

I'm doing my calculations using a developmental spreadsheet program used to develop the CheyTac ABC program. It has the capabilities to back calculate the BC values to the 4th decimal with extreme accuracy. What is needed is the initial muzzle velocity, the range, and the elevation setting from a parallel bore (not from the zero range, i.e. 100 yards). Parallel bore is usually about 4 MOA added to the elevation setting needed to strike the target at your range. For example, the 375/408 needed to 39 MOA from a 100 yard zero to strike at 2056 yards (these conditions). Add 4 MOA to that figure, you have a Parallel Bore setting of 43.00 MOA. That's a hell of a BC value. It's been check and verified and i'm building the G1 curve of changing BC values now.

Lots of explanation, but worth it.

 

[Black Diamond 408]

Trigger Fly;

Yes my 338 snipe-tac is based on the 408 case. Barney lawton made the original bbl for me about 4 years ago for this wildcat, we brain stormed on twist rates. I built a special action just for the 408 case. Chey-Tac actually asked me to build them actions at that time, but i didn't have the time to mass produce.

I have tried almost all powders that will work in the 338 bore. The US869 works just about the same as BMG50, WC872 shoots the best in my particular rifle.

Barney was telling me last year that lost river was working on a 375cal bullet.

What kind of groups are you getting with the 375 cal gun?

The 338 version is simply outstanding, between my version and Kirby's 338AM, we push the 300mk up to 3500fps. I like to shoot mine right at 3400fps, with groups at 500yds in the 1" range. At 100yds they are one holers. That says alot for the big recoiling cannons. The big 350grn 338 bullets will fly at 3250fps.
My gun is right at 16# with a detachable magazine. I mostly have customers that are interested in carry rifles for hunting purposes. My 10,3mm on the 50 spotter case is experimental for now, wonder what kind of range the 419 bullet would have if it reaches 3500fps. Pretty much all 408's run in the 2850fps range.


I will have some results on my new wildcat later this year, The 50cal spotter case has been changed to a 35 deg shoulder keeping the body taper intact. The shoulder has also been moved forward. The case has a very nice look to it. Overal length is 3 inches, loaded with the 419 LRB it is right at 4.300 long. This case resembles a Win Short Mag on steroids.

Dave

 

[triggerfifty]

Barney makes a good barrel doesn't he? I am using the 375 Lost River bullet. It's even better than the .408 bullets, when they were good. They had a short QC problem for a while, but these bullets are top rate. Typical groups at all ranges are from .5 to .75 to 1.00 MOA. Unofficial shots on steel plates that are 12" square at 2056 yards were shot after shot thru 7 rounds. I'll crawl into the rocks and take some pics of that. I plan to put a remote video on the plate and drill some rounds through it. These rounds also went through 1/2" cold rolled steel targets at 1000 yards (pics on my website).

You should try the 270 LRBT solid. In barney's barrel it should rock. I have no interest in LRBT and only push the best bullets, but at these speeds, jacketed bullets blow apart sometimes, as you know.

Do you make a detachable magazine setup for the 338 gun of yours? What is the mag length? Interested in joining forces on a repeater design of my 375/408 gun? I can supply mags that are .408 cheytac length +.300". The mags capture the shoulder of the cartridge and the tips of the bullets do not rest on the mags internals.

 

[James Jones]

Hey Dave their was some discussion about the pressure limitations with the 50BMG cases. I've heard that they won't go past about 50,000psi , it would seem to me that if you could find a way to get cases to handle pressures like the WSM's do (60,000+psi) that it would realy unlock the hidden beast in the big 50's case.
Like wise if the Chy-Tac case if able to handle pressures in the 60,000psi range how do you think a 408 case necked up to 50 cal would do?

I read an artical once about a 50bmg that Robar made , it was called a Desert Rhino , it only had a 18" barrel and they reported that their was only a 200fps velocity loss over the big Barret that the Marines use. If this is the case it seems that the 50BMG is a pretty effecient round and if a guy were able to get good brass he could build a 50 with a 24-26" barrel and not realy be loosing anything to the 36" barreld guns in production now

I don't know maybe I've been hanging around the NASA engeniers to much

 

[Black Diamond 408]

JD;

The BMG cases will go past 50,000 some fella's are loading them up too 65,000# That is max for any case due to brass becomes semi liquid at 70,000# The 50 spotter round is loaded with a 835gr projectile at 2350fps mil specs. That is moving for the large bullet and small case, there has to be some high chamber pressures there. The big thing is with the 50 cal case you get the larger case head and heavy webbing. The Action is larger and can take more thrust. Re-sizing the full size 50BMG case can be real fun if you run the loads hot, takes a hell of a press to handle that squeeze. I dont plan on loading mine over 55,000 for starters, but who knows where it will top out at. But so far this project is on the drawing table, test results are the only way to see how efficient the case is going to be.

Kirby is working on a 50cal in the chey-tac case, wont know the speeds until he shoots it, my guess is a 750amax around 2300fps. And yes the cases will take a beating.

Short bbl guns usually loose around 300fps over the standard length, that is why the long range pistol shooters can do so good with the same chamberings, 18-20" bbl lengths that is. I ran the numbers on the Snipe-Tac with a 20" bbl, it was right at the 300fps loss range. A 300grn MK pushing 3000fps out of a 20" bbl Would make a neat mountain rifle.

Dave

 

[Black Diamond 408]

Triggerfifty;

So far every Barney bbl i have got has been good, several 408's, 338's and a 308. All have been under 1/2moa.

I did have trouble with LRB 408 bullets in the past, they were to say the least, very eratic. I had several conversations with Warren about them also. He pretty much denied any thing wrong, i have heard they got rid of him but i have not used any of the LRB bullets since then. I still have several boxes left. We started using the Barnes bullets, they shoot very very good in the 408's. Aver groups are smaller than the LRB counterparts.

We have AR400 steel plates at our range, and few mild steel plates left over. The 300gr MK at 800yds with make a 3/4" dia hole through the 5/8 thick mild steel plate. The AR steel it will make splash dents in it. I can no longer shoot at any of the plates hanging at the range /ubbthreads/images/graemlins/grin.gif
I have to hang paper or bring my own plates. At 400.00 per silouete they say im wrecking them. A 300win mag just knocks the paint off of them. They accused me of shooting a BMG on the range, i said its just a 338 mag. They didn't believe me, so i had to show them. Like i said before, my first intention was to build the 375-408, but std hunting bullets wasnt what i was looking for, ok for out to 800yds i suspect.

 

[etisll40]

wtt