Allen Magnums, Long Range Bullet Updates...


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Jun 12, 2004
Fort Shaw, Montana
To all,

Well things are coming along nicely with the Allen Magnum rounds research. The reamers for the 257 AM and the 6.5mm AM have been finalized and ordered.

The 270 AM reamer will be ordered with a week or so.

I talked with Richard Graves, owner of Wildcat Bullets who is designing the bullets for these three new rounds and he had some extremely interesting news on the .257" and .277" bullets in particular.

This information will be of particular interest to us on this message board because it deals with long range shooting.

Along with high B.C. big game bullets for these rounds, we are also trying to develope some ULD bullets that will take these rounds farther and flatter then the 257, 6.5 and 270 have ever gone before.

Preliminary results with two bullet in particular seem extremely impressive. The first is a 145 gr ULD Rebated Boattail for the 257 AM. Richard tells me the initial B.C. reposts are that this bullet will produce a B.C. of .738 but he also feels that with a little tweeking this bullet will hit the .750 mark in B.C. with no problem.

These bullets are modeled for use in a 1-7 to 1-8" twist with the 1-8 being the best for the velocity range we will be driving them to.

Unfortunately Lilja does not offer this twist in the 257 but Pac Nor does and these barrels in their Super Match grade are certainly top grade match barrels.

The next bullet is for the 270 AM. This is a 169.5 gr ULD Rebated Boattail which is producing B.C. values of .748!!!

Again, this bullet will probably need a 1-8 twist, again not offered by Lilja but again Pac Nor does offer this barrel.

To put these bullets into some perspective, the 240 gr Sierra Mk in .308 runs in the .710 to .720 range in B.C.

The 300 gr Sierra Mk in .338" is producing a B.C. in the .780 to .800.

Now to get either of these two bullets to 3100 fps you need a very long barrel(+30") and a very large case capacity.

Recoil is also quite impressive without a 20 lb rifle or muzzle brake.

The 257 AM and 270 AM will produce velocities far over 3100 fps with these bullets and with recoil in the 7mm Rem Mag to 7mm RUM levels.

With a 9 lb rifle for big game hunting and a quality muzzle brake, these rifles will produce less felt recoil then a 25-06 or 270 Win but with the ranging preformance of the 30-378 and 338-378 Wby.

These were out performance goals from the start and it looks like things are going to hit their mark. There is still the ever important load developement but that will come in the next little while.

These rounds are shaping up even better then I had predicted!

Will keep you posted. There are some of these heavy ULDs on the way from Canada so I will post some pics when they arrive.

Good Shooting!!

Kirby Allen(50)

The initial rounds of the AM family are the 257 Allen Mag, 6.5 Allen Mag and 270 Allen Mag.

All three of these will be based on a highly modified 338 RUM case.

I selected the 338 RUM because of its slightly lower case capacity compared to the standard RUM which would be more case capacity then needed for these three calibers.

While the cases will be dramatically different then the parent 338 RUM in dimension, they will only need to be necked down adn fireformed so they will be very easy to use and I will be offering necked down parent cases.


Good Shooting!!

Kirby Allen(50)
Fifty Driver, Great to see the AM Magnum case project is progressing well.

I will be interested to see what the case capacities are for the final design, as that will determine whether the slowest powders, such as AR 2218 (H50BMG), H870, Viht24N41, and 20N29, are likely to achieve around 100% loading density with the 140 to 150 grain bullets.

After doing a little research on the web into velocities achieved by cases such as the 25/300 Win Mag, 25/8mm Rem Mag, 25/7mm STW, 6.53 Scramjet, I believe that your .257 AM has a very good chance of achieving the objectives you have listed.

The projected BC numbers on Richard Graves VLD bullets are certainly impressive and look forward to see how they perform.

I have ordered some of his 130 and 140 grain .257 cal flat base bullets. I intend to chronograph them in my 25/06 AI to see what velocities this "midget" case at the bottom end produces. Although I realise my 1 in 10 twist is unlikely to stabilise them.

Also, ordered some 85 grain & whatever is the heaviest he can produce in his 224 VLD dies, so I can order either 1 in 7.7 or 1in 7 twist barrel for my next .224 Clark.

My research into whoelse apart from PacNor produces 1 in 8 or 9 twist 257 cal barrels, found that:
Montana Rifleman list 8,10, &14 twist barrels. I note that they are in your State (Kallispell, Montana). Do you know of them, and what are their barrels like?
Shilen recommend a 1 in 9 for bullets over 100 grains, so I assume they produce it.
Badger Barrels appear to offer any calibre, contour and twist.
Krieger although only listing a 1 in 10 twist, has a note at the bottom of the webpage to call them regarding non standard twists, and bore and groove configurations.

Look forward to hearing more progress reports on your AM series. Regards, Brian.

The Dakota line of rounds are certainly a great line up of rounds. In fact I thought long and hard about using the 300 Dakota brass for the basis of my wildcat but after researching the Dakota round, I found that this case would only offer the same performance as the STW class rounds.

My goals were to significantly exceed this performance level and the AM rounds will do this easily.

Again, the Dakota rounds are great rounds but nothing more in performance then the STW class rounds. They can be stuffed in standard actions which is a real bonus but they would not produce what I wanted in performance, espeically with the new bullets from Wildcat Bullets.

Good Shooting!!

Kirby Allen(50)

The 130 and 145 gr flat bases are great bullets. Have been extremely accurate for me in the 257 STW and I am sure they will be as well in the AM.

Richard was telling me about a customer of his in Sweden I believe that tested some 142 gr Flat Base bullets out of his 1-10 twist 25-06 and put 10 of them into 1.1" I believe so they work in some 25-06 rifles appearantly.

I have noticed that with the thicker jackets on some of the Wildcat bullets, they really did not shoot well until the pressures got up pretty good. In talking with Richard, we both agreed that this was because the thicker jackets needed more pressure to bump up the base of the bullet which produced fine accuracy with these bullets.

So if they do not shoot great with starting loads be sure to run them right up to full pressures before you ever give up on them. It seems the Wildcat Bullets prefer to be driven very hard, the harder the better in some cases I have seen.

I am building a 22-6mm AI right now with a 30" 1-8" Lilja barrel for a customer and will be testing Richards 80 gr ULD's in this rifle. I am excited to see what this little monster will do.

I have not had alot to do with Montana Rifle Company for a couple reasons. First off, I have been using Lilja barrels for a long time and have no need to change. I also was referred to Pac-Nor barrels by my mentor in gunsmithing if you will and I trust his opinion and judgement on any thing gun related.

I have shot a few rifles built with these barrels and some shot well and others did not impress me. This had to do more with the fitting process I am sure then barrel quality.

I guess I just have not had a reason to try them with the other selections around.

I will not say anything bad about their barrels because I have not evaluated one that I personally have fitted and chambered but I will say they do not make the short list of top end barrels I am willing to use on one of my rifles.

I have all three AM reamers on order, should be here around the beginning to middle of December. I also have all three barrels on order as well which should be getting here the first of the year or a little before.

I have a Rem 700 BDL action in the shop that will serve as my test platform. This action is fully printed and accurized so I will just fit the barrels to this one action and test them all. Will save dramatically in R&D costs instead of three different complete rifles.

I will post all and any results I get here for everyone to see.

Good Shooting!!

Kirby Allen(50)
Kirby..this is Keith , you sent me that dummy round for the .257STW..just wanted to let you know that I'm still here and have been just hanging back a bit debating on what to do..mainly due to your new line up of carts your working on here! I'm really glad I didn't just send my action off to you right away because bye the sounds of these AM's I would be missing out on a real!!! .257 Screamer
Very interested in the R&D can't wait to here the results.

Thanks Again Kirby
On your ULD / VLD bullet

what the bullet lenght in caliber ?

How bullet are made , regular lead core on copper jacquet? and who make the jacket ? long jacket are made from redraw jacket in bigger caliber to get longer jacket ?

Good Shooting

Long Range Demon TacKac,


I was wondering where you were, good to hear from you again.

Alot of my customers are saying the same thing you are but they are a little unhappy at first, at least the ones that had me build them 257 STWs.

The nice thing about the AM rounds is that all that is needed to rechamebr a 257 STW to the better designed AM is to simply set the barrel back .200" and rechamber. The lose in barrel length will not even be noticed and only slight feed rail modifications are needed along with a RUM mag box in the repeaters, simple job.

THe reamers should be here in a couple weeks I am hoping and I have a 1-8 twist and 1-10 twist 30" barrel coming for testing this hot 257 AM round out fully.

I was totally floored when Richard Graves of Wildcat Bullets called and told me the B.C. of the 145 gr ULD bullets are initially showing a value of .738!!!

For the big game hunter the 150 gr BCFBHP will be right at .6 which with a S.D. of .324 with a bonded core bullet will be most impressive, especially when loaded to the 3400 fps level.

I will post any updates and especially the hard data when the rifles start barking!!

Good Shooting!!

Kirby Allen(50)

Richard Graves is handling all the bullet development so I do not have all the data and information you are asking.

I do have the length of the 257" 130 and 145 gr FBHP and FBSP bullets. They are:

130 gr BCFBHP---- 1.300"
145 gr FBSP------ 1.310"

The length of the 140 gr Bonded Core FBHP in 6.5mm is:

140 gr BCFBHP---- 1.320"

The 257 bullet in 150 gr BCFBHP and 145 gr ULD are being built as we speak and they should be here is a couple weeks for more information.

These are lead core, copper or guilding metal jackets. Richards has a variaty of jackets to use ranging from the J-4 which the 130 gr Bonded Cores are built on to very heavy tapered jackets which will handle any rotational stress these rounds will produce.

He also has several jacket makers that he used for different bullet needs ranging from match type bullets to serious big game bullets.

Yes to your last question.

Like I said, I am leaving the bullet details to Richard Graves, owner of Wildcat Bullets. I am just concerning myself with building the rifles and load development.

The design of the AM rounds was a cooperative effort of Richard and myself.

More information will be avaliable soon for these new and unique rounds.

Good Shooting!!!

Kirby Allen(50)
It's a shame that Wildcat Bullets does not have a website I would really like to take a look at them ...just wondering ,,Kirby would I be able to gain anything by going to these over the 300 SMK in my .338's set up to shoot the 300's so twist is not a problem's a 9..and somthing a rather
I know it's just shy of a 1-10 but it shoots the 300 really well ...but allways looking for something better you know how that goes lol. Yeah I bet some of your more recent customers may be a liitle upset after chambering for the .257 STW and then hearing about these kick *** carts your working on...but heck from what I know about you so far your a man that keeps his word and is very Eager to please ...I'm sure they will be happy soon.
Anyways Kirby it's good talking to you again and I check in here all the time, so I will keep an eye out for your development on these things. Thanks again Keith
dave--i will get a pic of his 142ULD next to a 142 sierra and 140 amax for comparison

will probably post it tomorrow

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