More 257 Allen Magnum range results....

[Fiftydriver]

Today I was able to take two of my Extreme Sporter rifles out and do some testing with the 257 Allen Mag. One rifle is a 1-8 twist and the other is a standard 1-10.

First up I tested a prototype bullet designed by Richard Graves of Wildcat Bullets. This is simply one of the most impressive bullets I have ever worked with and that includes the 300 gr ULD .338" bullets and the 50 BMG pills.

The bullet in the middle is the 156 gr ULD RBBT prototype bullet. On teh laft is the 130 gr BCFBHP Wildcat and on the right is a 100 gr Nosler Partition.

The 156 gr Wildcat is built off a heavy tapered jacket designed specifically for big game hunting. IT weights 156 gr and is a rebated Boattail design with a B.C. in the +.800 range. Have not done quite enough testing to get an accurate B.C. but I am thinking it will be in the .820 range.

Anyway, with a load of 93.0 gr of AA8700 over a Fed-215 primer and the bullet seated 0.010" off the lands the fist shot out of the freshly cleaned barrel impacted about 2" high and center. The next three landed roughly 1" above the first in a three shot group that measured .274" ctc at 100 yards. Extremely impressive for an extreme length bullet like this at this short range.

I was hoping for a velocity in the 3200 fps range and had determined that a load of 95.0 gr just started to loosen primer pockets so I dropped the powder charge two full grains and determined this was the max working load in this rifle.

I was a bit concerned how the 8700 would perform as far as velocity consistancy but the chrono reading showed the following for these four shots:

3370, 3357, 3360, 3372 fps for an average of 3365 fps and an extreme spread of 15 fps. Still this is only for four rounds but it looks like with a little seating deptth tinkering, E.S. numbers will be in the single digit range.

I will next test this load at 500 yards and see how the bullet performs as far as stability is concerned. Then I will decide if I want to stay with the 1-8 twist used here or go with the 1-7.5" twist for a little added stability insurance in cold weather or at extreme range.

Still with a velocity in the 3350 fps range and a B.C. of +.800, this 1/4 bore magnum will have few peer as an extreme range deer and pronghorn load as far as trajectory and wind drift are concerned.

My 338 Kahn will match this bullet in B.C. but not in S.D. or even close in velocity. We will see how she does at some longer ranges.

Next up is a bullet for those that love speed. This is teh 100 gr Bonded Core FBHP Wildcat Bullet. This little pill still has a B.C. of .500 so it shoots supprisingly flat for a 100 gr .257 bullet.

The test rifle used to be a 30" 257 STW and as an STW, it would drive these same bullets to 3950 fps with a max load and group in the .3's and .4's at 100 yards.

I rechambered the barrel to the shorter and fatter 257 Allen Magnum which needed the barrel to be shortened by .250" to clean up the old STW chamber.

I loaded up test loads with 8700 starting at 104.0 gr and stopping at 109.0 gr.

Here are the velocity results for each powder charge:

104.0...................4224 fps (oily barrel)
105.0...................3972 fps
106.0...................4082 fps
107.0...................4089 fps
108.0...................4093 fps
109.0...................4076 fps ???

It is clear to see that after 106.0 gr, there was no meaningfull velocity gains. Even at this level, the 257 Allen Magnum is topping the 257 STW by nearly 130 fps.

Obviously the light 100 gr bullet is not offering enough resistance to the powder to get any velocity gains over a certain charge level.

Still, the 257 AM is producing 4100 fps class performance. The 257 STW has been falsely advertised to be able to do this with a 28" barrel when in all honestly, the STW will only generate around 3850 fps with a 100 gr pill in a 28" pipe.

I shot these test loads into two three shot groups, the first three in one and the second three in another, here are those two groups:

The 109.0 gr load is the high impact on the right group. I am not sure why the shot fell out of the group or why the velocity dropped, may be a result from a bad case.

Still, if I had shot all six at the same target, the total group size would have only been .662" ctc for all size shots. Not to bad figuring they were all different loads.

Next I will load up test groups at 107.0 gr and again at 109.0 gr and see how they perform on average in groups and in velocity consistancy. If there is no real velocity advantage with the heavier charge, there is no reason to burn more powder just to do it.

Richard Graves is also building a very heavy tapered jacketed 100 gr pill for use in this round which will do a couple things. First off it will handle the impact velocity much better then this thinner jacketed model designed for the 25-06 and 257 Wby.

Second, the thicker jacket will offer more resistance to the powder charge and will help improve powder burn at the higher charge levels.

4100 fps with a .500 B.C. 100 gr bullet will be pretty darn flat shooting out to 500 yards for the ultimate pronghorn rifle.

I will repost how the velocity variation tests go with the 100 gr pills and how the big 156 gr ULDs do at 500 yards.

Good Shooting!!

Kirby Allen(50)

 

[bailey1474]

I have to admit these results are very impressive. My question is: How practical is this round? The bullets you showed have phenomenal BCs. Are they as pricey as Lost River? While the performance is great, I just can't justify it if the bullets are going to cost $2 apiece. If these bullets are reasonable, my 300 RUM will be rebarrelled w/a .257 cal.

 

[Fiftydriver]

Bill Bailey,

I assure you that no WIldcat Bullet is even remotely close to the price of the LRB bullets.

The spendiest bullet Richard makes so far onhis price list is his .338" 300 gr ULD which run around $75.00 per 100 bullets and thats Canadian funds. Comes out to around the $58.00 per 100 bullet range.

These bullets will be much less but as a prototype bullet I do not have a price yet. I will contact Richard and see what he is thinking about price. His 270 and 7mm match bullets are running around $38.00 per 100 bullets but these new 257 bullets do have a differnet jacket so I will find out for you from Da Man himself.

If I had to guess, I would be supprised if they ran more then $0.45 each American but I will find out for sure. Nothing like the LRB bullets I assure you. And these are heavy tapered jacketed bullets with lead cores designed for use on big game as well as producing match grade performance.

I will get back to you on the bullet price.

Good Shooting!!!

Kirby Allen(50)

 

[bailey1474]

Wow!!! That is about on par with the retail price for Barnes!!! I'll probably have to wait a year or two on the rebarrel job, but maybe by then you'll have all the bugs worked out of the wildcat.

In the meantime: How do I get hold of Richard. I would be very interested in some of his 30 cal. bullets. Any info you could give me would be greatly appreciated.

Thanks,
Bill Bailey

 

[Fiftydriver]

Bill,

Talked with Richard this morning and he said he did not have an exact price figured up yet but he said they would be in the $43.00 to $45.00 per 100 bullet range in US dollars. Not bad at all for what you get.

Richard also said he just made some 169.5 gr Rebated Boattails in .308 that are shooting extremely well.

You can contact him at:

[email protected]

Great guy to talk with and knows his stuff on bullets.

Drop him a line and he will respond within a day or so.

Good Shooting!!

Kirby Allen

 

[Jimm]

50driver,considering a new rifle in .308 cal.. should i go with my favorite (300 winnie) or the new 300 wssm. is it so important to get rid of the belt?pros ands cons please thANK YOU, JIMM

 

[Fiftydriver]

Jimm,

Only thing I do not like about the standard belted magnum case is that when you cut a chamber to min specs you will occasionally run into cases with a headspace dimension(base to forward edge of belt) that varies enough to make the case bind a bit in the chamber.

This can be solved by cutting the chamber a bit longer or by sorting brass.

This is also a problem with the WSM and RUM brass but the shoulder will conform to the chamber on firing, the solid belted Magnum head will not change dimensionally when fired.

This is really my only real problem with the standard belted Magnum case.

The 300 Win is a great round. Will out run the 300 WSM by a solid 100 fps. As far as extreme range potential, when both are set up in a quality rifle with a match chamber, the x ring will be in trouble at 1000 yrds no matter which chambering you choose.

Personally, my decision would depend on if your rifle is set up as a repeater or a single shot. As a repeater I would choose the Win Mag because it is a better feeding round then the short little WSM, even with its belt.

In a single shot, I would choose the 300 WSM simply because it is a bit more efficent, barrel life will be slightly longer, not enough to worry about and in theory this case design is inherently more accurate.

Personally I feel the rifle makes the accuracy and not the round. Really, there are no flies on either. As I stated, the only thing I really don't like abou the belted Mag is what I mentioned above.

Avvuracy wise, they will both produce 1/2 moa out to 1000 yards in a quality rifle with true match grade ammo.

If you will be shooting the real heavy weight bulles such as the 240 and 250 gr ULDs, the 300 Win would be my choice because of its larger boiler room.

Good Shooting!!

Kirby Allen(50)

 

[ajones]

wow, very impressive post Mr Allen. I have been considering building a longrange shooter on the .257 cal. Would you explain what the parent case is for your 257 magnum? thanks in advance.

 

[Fiftydriver]

Dogdinger,

My 257 Allen Magnum and the 6.5mm Allen Magnum are based on the full length 338 RUM case. This case is 0.100" shorter then the other RUM rounds and as such offered the maximum usable case capacity. The shorter case holds about 8 gr less then then say a 7mm RUM fireformed to teh Allen Mag shoulder configuration.

The case is nearly absent of body taper, about 0.008" over teh entire length of the case body. The shoulder angle is also increased substantially over that of the 338 RUM but not quite to Ackleys 40 degree shoulder.

CAe capacity filled to the mouth with H-335(settles evenly) measured 123 gr.

I am offering pre neck sized cases that will be properly sized and then annealed as the brass is work hardened quite severely going from 338 to 257.

The necked down and annealed cases will run $38.00 per 50 cases plus shipping. All that will be needed is to load a fireformign charge and shoot. Then trim and your ready for full tilt loading.

Because this round is such an extreme performance round, there has only been one powder that has produced excellent results with all bullet weights tested including the 100, 115, 130, 145 and 156 gr bullet weights. That powder is AA 8700.

The bad thing is your limited to one powder, the good thing is it works great with all bullet weights and is much cheaper then most reloading powders on the market.

This powder will drive a 100 gr pill to 4100 fps with groups in the .3"s as well as drive the huge 156 gr ULD bullets to +3350 fps in one of my 30" Extreme Sporter rifles.

Using this huge 257 bullet, this will make an excellent extreme range rifle as it has a B.C. higher then a 300 gr Sierra Mk .338" bullet and can be launched 250 fps faster then even the 338-378 Wby can drive the 300 gr pill.

This bullet will stay supersonic past the 2000 yard mark easily.

I will be building myself one of my V-Block rifles in this caliber probably this summer.

Lilja will be making the 1-10 and 1-7.5" twist barrels for the 257 AM.

Good Shooting!!

Kirby Allen(50)