I am developing a big 257 wildcat at this time that will be a member of an initial line up of three calibers, the 257, 6.5mm and 270.
I am working with Richard Graves of Wildcat Bullets to take these three calibers to performance levels never before realized.
Our performance goals are to compete directly with the 30-378 and 338-378 class of rounds in trajectory and wind drift and so far it looks like this will be easily accomplished.
First off, about the round. I am using a 338 RUM case that will be extensively modified from its original form, same length, just much different shoulder design and diameter. Specifics are not being offered at this time but I will say I am expecting to get at least 150 fps more velocity then anything the 257 STW can get out of equal length barrels.
Perhaps the most unique feature of these new rounds will be the bullets used in them from Wildcat Bullets. These bullets were designed especially for the 257 Allen Magnum round to satisfy the special demands of this huge 257.
I have built many 257 STW and have been very impressed with their velocity but the 257 STW's claim to fame has always been a 100 gr bullet at near 4000 fps. This provides very flat trajectory but even the best 100 gr bullets B.C. is only in the .480 range and that is the 100 gr Bonded Core FBHP from Wildcat Bullets.
I personally like heavier, higher B.C. bullets for long range shooting. For this reason, Wildcat Bullets has designed three new bullets and is working on a fourth for the 257 AM round.
They are the 130 gr Bonded Core FBHP(B.C. .550), 145 gr FBSP(B.C. .550), 150 gr Bonded Core FBHP(B.C. .600) and finally the 145 gr ULD Rebated Boattail(B.C. of .738 on initial testing).
These bullets offer performance above anything ever seen in the .257" bore previously.
To match the 30-378 and 338-378 class rounds in long range performance, we needed high B.C. but also high Sectional Density numbes and high velocity.
Here are the Sectional Density values and other bullets they compare to:
130 gr BCFBHP------.281
145 gr FBSP--------.314
150 gr BCFBHP------.324
7mm 162 gr---------.287
338" 250 gr--------.313
308" 220 gr--------.331
So as you can clearly see these new .257 bullets will either come very close to or beat some of the highest B.C. bullets on the market.
What will set them apart will be the velocity produced with these rounds in my rifles. They will be designed around 30" barrels in sporter style rifles that will weight in at 9 to 9 3/4 pounds. Pretty light for a 30" barreled rifle.
They will run very well out of anything 26" and over but they will be originally designed around this rifle platform.
Velocity expectations are as follows with these bullet weights:
115 gr---------3850 to 3900 fps
120 gr---------3800 to 3850 fps
130 gr BC------3600 to 3650 fps
145 gr FBSP----3450 to 3500 fps
150 gr BC------3400 to 3450 fps
145 gr ULD-----3400 to 3450 fps
These velocities are pretty conservative in my opinion with a 30" barrel but I would rather lean toward conservative numbers then blow the velocity potential all out of the water like most of the manufacturors do. I actually expect to hit or exceed these velocities in rifles I ship out the door.
Now if you take these bullets, with their high B.C. and S.D. combined with the velocity potential the AM round will produce, youcan clearly see that the 30-378 and 338-378 will be hard pressed to keep up with these rounds.
For extreme range shooting, the 240 gr SMK has similar B.C. values to the 145 gr ULD .257" bullets but still less and the 257 AM will have a dramatic velocity advantage with a slightly higher B.C.
All you have to do is see how fast the 30-378 will drive the 240 gr pill and it is clear the 257 AM will out perform it at extreme range.
The 338-378 certainly has an edge in B.C. with the 300 gr VLD and ULD bullets but again, this round is hard pressed to get over 3100 fps out of a +30" barrel where as the little .257 AM should easily be able to hit 3400 fps.
Also, recoil will be about 1/3 that of the big hammers and because of the lighter bullets, barrel torque will be less allowing for a lighter contour barrel to be used and still remain accurate at extreme range.
If you would like more information, drop me an e-mail at:
I will get you some photos of these rounds and the Wildcat Bullets that will be used in them compared to conventional 257 bullets.
This round will perform great out of either a light rifle or a barrel bedding V-Block design, which ever suits your needs best.
From the research done on these rounds, I feel this is the largest case capacity that is usible to full effect in the 257 bore, and then only with the heavier bullets mentioned above.
The 257 Banshee is built on a blown out and improved 8mm-68 case and it roughly is the same as teh 257 STW in performance, just a bit shorter and fatter, great design though, expensive to make though and cases can be hard to get.
The Lapua case is also very expensive and my AM will provide identical capaacity to this case.
Forming cases will be simply a fireforming process similiar to the Ackley rounds. I will be providing necked down brass that will only need to be loaded and fired for the AM cases.
I am also working with Redding as we speak on the dies.
Let me know if your interested, Reamers will be here aroudn the first of December so rifles will be going out by the first of the year I hope.