Originally Posted by TXAoudadKlr
What are the velocities being obtained by the 416-408cheytac wildcats?
The 416 barrett shoots 400gr's at 3150-3200 right?
The 416 barret was originally listed with a 398 gr solid driven to 3250 fps. Since its release, its been downrated to 3150 fps and the three rifles I have shot in this chambering using Barretts own ammunition clocked an average of 3090 fps with a 400 gr solid. Now with some handloads using WC-860 and US869 we were able to get up to around 3150 fps which again is what they are listed at now. Problem is, that proper chamber pressure for the 50 BMG class head diameter is roughly 55,000 psi. This is because the HUGE head diameter generates EXTREME bolt thrust, even for the massive receivers designed for the BMG class weapon systems. TO check for proper chamber pressure, you should be able to fire a round, eject the fired case, put it back in the chamber and close the bolt on the just fired case with very little resistance on the bolt handle. IF there is noticeable resistance closing the bolt on a fired case, your 60,000 psi or heavier because you are permanently deforming the brass, again, this is the standard pressure checking method for any round based on the 50 BMG. If your loading hotter then this, your loading the case FAR over what it was designed to be loaded to.
Now to the 408 CT wildcats, let me explain my experience with this parent case. About 8 years ago I released my 300 Allen Magnum and 338 Allen Magnum and soon after that my 375 Allen Magnum. Then came the 410 AM and 50 Allen Tactical all based on this parent case.
The 300 AM proved to just be to large in case capacity for the 30 cal bore and did not work well at all, even with custom 300 gr class bullets(300 gr 30 cal ULD RBBT is something to see!!!). As such it was dropped from my option list for customers.
The 338 AM is a 408 CheyTac necked down to 338 with the shoulder location moved forward roughly 0.080" and shoulder angle sharpened dramatically over the parent case. Also body taper is increase as much as possible yet not to much to limit high pressure extraction performance. At the time I released the 338 AM, I was working VERY closely with Richard Graves who was the owner of Wildcat bullets at that time. He made me versions of his ULD RBBT in weights from 265 gr, 300 gr, 325 gr, 350 gr and 385 gr. In a 32" barrel length, the 338 AM could easily hit 3450 fps with the 300 gr SMK and 3250 fps with the 385 gr ULD RBBT using the old TTI brass. That was with at least a 6 firing case life.
About this same time CheyTac contracted with Jamison International for them to make their brass for them. I also contracted with Jamison to start making me correct headstamped brass that I could fireform so my customers could have correct headstamped, fully formed brass for my 338 and soon to be released 375 Allen Magnum wildcats.
The first brass I got in some of you may remember was referred to as the "double star" brass. This is the EXACT brass that Chey Tac was using for their factory loaded ammo. In my first tests with my new correct headstamped brass, I blew the primer pockets out on the first starting loads!!! I contacted Jamison about the problem but they said the brass was made to Chey Tac standards and they had no interest in stronger brass as their intent was for only one firing per case......
Well, about a month later Jamison must have been getting a lot of bad press because they hired a new team to come in and help them redesign the CT case so it would handle more pressure. THey sent me prototype cases to help pressure test using my 338 AM and 375 AM rifles just to see if my velocity results were similar to what they were seeing with good brass life. It took around 8 months but they finally came up with a case that could handle good working pressures. Not as strong as the old TTI brass but DRAMTICALLY better then the original design.
In the old brass, CheyTac loaded the 375 Cheytac with the 350 gr SMK to 3100 fps and the 408 Cheytac was loaded to around 2900 fps with the 419 gr projectile. With the new brass, these velocities were increased to 3200 and 3000 fps respectively. They also had a 305 gr option in the 408 CheyTac that was listed at 3200 fps.
Now, in my testing NONE of their ammo came with 100 fps of their advertised velocities but that's not uncommon with factory ammo. handloads with this new brass was easily able to be loaded to their listed claims.
My 375 AM was able to drive the 350 gr SMK to a max velocity of 3375-3400 fps with my accuracy load being in the 3280-3320 fps range.
I have only played with my 410 Allen Magnum in one rifle which is basically an improved version of the 408 CT made with my case shoulder design and body taper. With a 400 gr class bullet it will push 3200 fps very, VERY hard with a max charge of H-1000 or RL25. Retumbo gives a bit better velocity consistency but drops max velocity potential to around 3100 fps.
So, for a direct comparision, the 416 Barrett will drive a 400 gr class bullet to around 3150 fps and do so in a 50 BMG class weapon system in both size and weight.
You can build the 408 CheyTac into a repeating rifle that would weigh less then 18 lbs pretty easily and that would with with a 7 round detachable magazine box. Not only that but you can drive a same weight bullet to within 100-150 fps easily and do so with 50-60 grains less powder.
With the improved versions, you can get within 25-50 fps of the much larger 416 Barrett with same lighter rifle and much more compact ammo which again offers the dramatic improvement in barrel life over the Barrett and also opens up a HUGE array of powder choices. Anything from H-4831 to Retumbo will work very well.
So how is this possible, HOW can the dramatically smaller round match the performance of the MUCH larger 416 Barrett, simple, the case head of the Chey Tac is DRAMATICALLY smaller in diameter compared to the 50 BMG. As such, if you put 68,000 psi to the head of the 50 BMG, you would likely lock up even a 50 BMG class bolt. IF you put 68,000 psi to a cheytac case, the bolt will fall open and work perfectly well. Add to that the ability to use MUCH better powders which will generate much better velocity and also offer longer barrel life.
You would be dealing with 125-140 grains of powder in the 408 CT or its improved siblings depending on what powder was used compared to 190 to 200 grains of a very narrow selection of powder used for the barrett. That's 60 to 75 grains more powder for an extra 150 fps over the standard 408 Cheytac.........
Now, I am not saying the 408 is better then the 416 cal. Not at all, in fact, with the release of the 416 Barrett, there has been much more bullet activity then in the 408 cal bullet family. For that reason, the 416 is far better, but its a simple matter to neck up the 408 to 416 and get a few more bullet options as well.
Velocities compared between the 408 and 416 cal bullets of same weight over the same capacity are extremely similar. The 416 may be able to get an extra 25-35 fps with same bullet weights but that would be effected more by barrel to barrel variations.
Another example of how the Cheytac case can run very close to even the full length 50 BMG. THe standard 50 BMG loaded to a conventional max 55,000 psi will drive a 750 gr A-Max to 2650-2700 fps. In fact many 1000 yard BR shooters load their ammo to lower velocity then this but this is a pretty common velocity range for match quality accuracy.
My 50 Allen Tactical will drive a 750 gr A-Max to 2500 fps in a 30" barrel length. That is using RL19, RL22 or H4831. Now, that is with a powder charge of around 120-125 grains in the 408 CT based 50 cal round to get 2500 fps and that is in a 16 lb single shot rifle.
The 50 BMG will get 150 to 200 fps more velocity but in the mean time you will burn 215 to 235 grains of powder depending on what powder you use. And, again, add to that a 25 lb minimum rifle weight. Is an extra 100 grains of powder with 150 to 200 fps...... If you want a 50 BMG class weapon system, certainly.
Now, the 50 BMG CAN be loaded to higher pressures and push velocity higher but again, if you load the round to its design specs, it will not get that level of performance. Most velocity reported on the 50 BMG is with a 45" M2 browning barrel, not a 30" class match grade barrel.
So, what does all of this mean. The long winded report was simply to offer you my experience with both case designs and finding out the limits of each in 338, 375, 408 and 50 cal and comparing the Cheytac case to the Barrett and even full length BMG case. In every case, the Cheytac will get within 100-150 fps to the Barrett or 50 Spotter case and the improved wildcat versions will get within 50 fps of the listed factory specs for the Barrett.
This may surpise many of you but its simply the facts. The huge case head diameter of the 50 BMG is actually a draw back limiting the pressures it can be loaded to and the reason the 408 CT case can run very close on its heals, simply its ability to run at higher chamber pressures and to use much better powders that produce better velocity in shorter barrel lengths.
Nuff YACKING on my part. Hope this explains the comparision well enough.