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Rifle build

 
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  #8  
Old 07-01-2005, 08:52 AM
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Re: Rifle build

257 Speed,

I only have prototypes right now. From what Richard tells me, they do not even compare to the production bullets, we will see, supposed to be getting a big shipment of them in soon. Generally when Richard is impressed with a bullet, it is a pretty impressive bullet.

For some reason, Hunt101.com is not allowing me to upload the picture of them so I will try later and see if it will accept it???

Kirby Allen(50)
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #9  
Old 07-01-2005, 09:04 AM
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Re: Rifle build

Jrdoty,

Barrel changes really depend on whats need to set up headspace. Some barrels will bolt on as is and for those generally $20. If the headspace is long on the new barrel it is a simply task to take a bit off the barrel shoulder to bring headspace into spec, for this $50.

If the headspace is short, significantly short where truing up the bolt lugs and botl face will not bring a barrel into headspace spec and the chamber must be lengthened then yes it would run in the $150 to $175 range.

My 7mm Allen Mag is based on a full length 338 Lapua case with the Allen Mag shoulder configuration and min body taper. For comparision, my 270 Allen Mag based on the 7mm RUM case has a case capacity filled to the mouth with WC872 of 124 gr. We are predicting the 7mm Allen Mag will be at least 135 gr capacity with basically the same neck length and volume so it will be a +10 gr capacity increase.

Also, the shorter case length of the 7mm Allen Mag will allow the long ULD bullets to be seated out of the powder capacity much more then the 270 Allen Mag offering an even greater usage of the cases capacity.

Another advantage is the strength of the Lapua case. This case will handle higher loading pressures then the RUM case and as such will have an even greater velocity and performance advantage then the case capacity would have you believe.

This is not to say the 270 AM is not a great round. It is a fantastic round, the 7mm AM will just be different in a couple ways and as such will also be a bit more expensive to build. especially in a repeating form.

Redding is already in the process of building the Full Length sizing dies and I will be furnishing the BR in-line seating dies chambered with the same reamers used in the rifles.

We are predicting 3200 fps with the 200 gr ULD in a 30" 1-7 twist 3 groove Lilja barrel. This with a B.C. in the very high .9 range should result in some amazing ballistic numbers.

The best thing is that the 200 gr ULD RBBT as well as the lighter 175 gr version are built on a tapered jacket designed for use on medium big game at any range.

I am hoping to take a couple days this weekend and get my 7mm Allen Mag test rifle built and on the range so I can report on this new hot rod 7mm. We are looking to top the Lazzeroni 7.21 Firebird by at least 100 fps in velocity with all bullet weights. We also hope to get 3900 fps with a 140 gr Bonded Wildcat or Accubond for those that want the ultimate 600 yard pronghorn rifle with lazer flat trajectory!! We will see what happens.

Good Shooting!!

Kirby Allen(50)
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #10  
Old 07-01-2005, 10:40 AM
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Re: Rifle build

3200 fps out of a 30" barrel. I think your being fairly modest. the barnes reloading manual shows 338 lapua shooting 200 grainers at over 3300 fps and shows the 7 stw shooting 195 grainers at near 3000fps both with only a 26" barrel. I think your going to be closer to 3400fps with the 200 grain wildcats, but im sure you know a lot more about it than me. Either way i think your going to need a really good muzzle brake. I can't wait to here the results of your testing.
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  #11  
Old 07-01-2005, 11:12 AM
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Re: Rifle build

jrdoty:

If you do a search on Kirby and Richard you will find that they are usually conservative on their estimations of the cartridges and bullet combinations they design.

Donít be surprised to see him exceed his estimations. [img]/ubbthreads/images/graemlins/grin.gif[/img] I, for one, hope he does exceed it by a lot. It will be a very impressive round to say the least.
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  #12  
Old 07-01-2005, 12:16 PM
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Re: Rifle build

A 7mm on a 338L sounds good. Hope it works out well.

I guess I better go and get the penny jar down and see how many is in there. Then I need to update how many days I got left doing 8 to 5 /5 days a week.
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  #13  
Old 07-01-2005, 01:04 PM
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Re: Rifle build

Jrdoty,

Be careful comparing a 200 gr 338 bullet to a 200 gr 7mm bullet. They are extremely different animals to deal with. The baring surface length along is dramatically different for the two bullets.

Also remember that in a 338 Lapua loaded with a 200 gr bullet, the powders that you are able to use safely are dramatically faster burning then what can be used in a round like the 7mm Allen Mag. The combination of the faster burn rate powders with the shorter baring surface combine for the ability to get very impressive inital velocities.

The key to making a realistic comparision is to get bullets with similiar sectional densities.

This is not exact but it gives you an idea what you are comparing. For example, the 200 gr ULD RBBT has a sectional density of .354. For a 338 bullet to equal this it has to weight 285 gr.

Now put that into the comparision. How fast will a 338 Lapu drive a bullet with a sectional density of .356 compared to the 7mm Allen Mag velocity with a bullet of the same Sectional density.

A 338 Lapua will probably get into the 2800-2900 fps range in a 30" barrel, we are predicting the 7mm Allen Mag will hit 3200 fps with the same barrel length.

On top of that compare BC values. A 338 Lapua with a 300 gr ULD or VLD is a 2800 fps round in a 30" barrel and these bullets will have a B.C. in the .790 to .820 range depending on bullet used.

The 7mm Allen Mag should hit 3200 fps with a 200 gr ULD RBBT and from eveything we have seen on the computer model projections, this bullet should produce a BC in the high .9 range.

As far as the 7mm STW goes, I have yet to see one hit a solid 3200 fps in a 26" barrel with comfortable working pressures and long case life. Add 35 grains of bullet to that and I would bet you would be hard pressed to reach 2850-2900 fps unless your using a bore riding bullet.

Also remember that in a relatively small bore like the 7mm shooting 200 gr class bullets, 200-300 fps increases are extremely significant performance boosts.

Yes we tend to be conservative but that is only because we want to be honest and practical with you. We see far to many guys listing these extreme velocity numbers for their wildcats only to have their one personal rifle ever come close to those specs.

I would rather predict low and have my guys extremely happy that they are getting more from their rifles. So yes we both tend to be on the conservative side on performance predictions and so far all the Allen Mags have outperformed out goals, I hope the 7mm and 338 will be the same.

Good Shooting!!

Kirby Allen(50)
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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