Long Range Hunting Online Magazine

Go Back   Long Range Hunting Online Magazine > Rifles, Reloading, Optics, Equipment > Rifles, Bullets, Barrels & Ballistics

Rifles, Bullets, Barrels & Ballistics Applied Ballistics


Published vs. Actual Ballistic Coef.?

LinkBack Thread Tools Display Modes
Unread 06-06-2005, 01:28 PM
Official LRH Sponsor
Join Date: Jun 2004
Location: Fort Shaw, Montana
Posts: 6,841
Re: Published vs. Actual Ballistic Coef.?

Derek M.

Johns wildcat is basically a 7mm STW with a custom accuracy throat very similiar to the one I use in my rifles. The 7mm STW will run in the 3400 fps range with a 150 gr bullet. I believe John used X bullets but can not say for 100%.

The 150 gr X bullet will have a B.C. in the .500 range. Compare that to the 169.5 gr ULD with its .750 BC and the ballistic difference is clear.

Barrel life of the two rounds will be within 150 rounds of each other I would guess, especially using the WC872 powder in the Allen Mag.

Out to 400-500 yards the ballistic difference will be very little, past that though the 270 Allen Mag will be maintain more velocity and it always has far more bullet energy at any range. Wind drift at extended ranges will favor the 270 Allen Mag as well simply because of the BC advantage.

IF you want to compare the same bullet in each rifle, the 270 Allen Mag will drive a 150 gr bullet to nearly 3600 fps with top loads.

Still for long to extreme range shooting and hunting, the 169.5 gr ULD is far superior to any conventional bullet design for the 270 or 7mm commercial bullets.

The 7mm Allen Mag is a totally different cat then the smaller Allen Mag rounds. It to can be chambered in the Rem 700 receiver but it is based on the much fatter 338 Lapua case with the Allen Magnum shoulder angle and body taper design.

These rifles will be on the test range by the end of the summer.

They will be more costly to build unless they are converted to single shot. A repeating model will be offered on the Rem 700 receiver using the H-S Precision Detachable Magazine system. This system alone adds roughly $200 to the rifle price.

Initial performance expectations are to drive the 200 gr ULD RBBT Wildcat Bullet to a solid 3200 fps. This bullet should produce a BC in the .950 range so ballistic potential will be far superior to even the 270 Allen Mag and vastly more then the 7mm RUM.

We are looking to add roughly 100 fps to the performance of the 7.21 Firebird from Lazzeroni with far better quality brass.

We are expecting to drive a 140 gr Accubond to +3800 fps possibly 3850 fps. Again the light weight bullets look impressive in velocity but it is the huge 200 gr ULD RBBT Wildcat that will make this round truely special.

Still it will not be as easy to use as the 270 Allen Mag simply from a case forming aspect. Also, the rifles will be more costly to build as well as a repeating rifle.

Good Shooting!!

Kirby Allen(50)
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:
Reply With Quote

Unread 06-07-2005, 11:38 AM
Platinum Member
Join Date: Jul 2004
Location: OHIO
Posts: 2,417
Re: Published vs. Actual Ballistic Coef.?

Ok, Kirby, here's where we are: I called Bass Pro and they sold that leftie. I went to a local store, the Gun Runner, and his supplier has 1 left handed 7 RUM all stainless LSS left at $616.96 which comes to $700 for me. I'd be better off getting the left hand stainless action from you for the price you quoted, however, you might want to make sure you can get it so I can order this one locally if you cannot. AND, this guy is closed tomorrow (WED)!!

I don't know how often you check your email, but I sent this to you already. Do you take personal checks? I'll be sending you my HS stock anyway to build the rifle. Plus I'd like you to cut off the Uncle MIkes recoil pad and replace it with either a Pachmyer Decel or the Rem3 made by limb saver. Also, let me know if you can modify LOP to about 12.5 to 12.75". I have short arms and when I get extra clothes on in the cold it really affects LOP. My draw length for my bow is 28".

If we cannot arrange for me to have the stainless action (which I really prefer now that Remington has discontinued it as well as BDL's and ADL's), I can always get a remaining CM blued leftie.

CHECK YOUR EMAIL! [img]/ubbthreads/images/graemlins/grin.gif[/img]
Derek M.
Reply With Quote


Thread Tools
Display Modes

Similar Threads for: Published vs. Actual Ballistic Coef.?
Thread Thread Starter Forum Replies Last Post
Swift bullets published BC's cornstalker Rifles, Bullets, Barrels & Ballistics 8 03-19-2011 07:18 PM
Published Muzzle Velocities..accurate or not? Seven Oaks Long Range Hunting & Shooting 11 06-02-2009 10:55 PM
Chrony readings vs published data Kris C Rifles, Bullets, Barrels & Ballistics 3 05-08-2009 08:46 PM
Varmint Hunter Association Magazine Articles To Be Published On Our Site Len Backus General Discussion 12 06-02-2008 07:31 AM
338 250 GR SMK ballistic coef. Rifles, Bullets, Barrels & Ballistics 2 09-25-2003 03:29 PM

All times are GMT -5. The time now is 04:43 PM.

Powered by vBulletin ©2000 - 2016, Jelsoft Enterprises Ltd.
Content Management Powered by vBadvanced CMPS
All content ©2010-2015 Long Range Hunting, LLC