270 Allen Mag, Extreme Sporter Range test...

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Fiftydriver, Apr 4, 2005.

  1. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    To all,

    Been preparing for an exotic sheep hunt to field test the 257 and 270 Allen Mags. The hunt has been bumped back a week or to as we were supposed to be hunting today /ubbthreads/images/graemlins/frown.gif...

    Thats alright through, give me a bit more time to do a little more testing.

    Anyway I wanted to test the 270 Allen Mag at some longer ranges so I drew up a drop chart using the muzzle velocity along with the 100 and 450 yard impact data and headed up to the range.

    I set up the exact same target as I did for testing the 338 Kahn at 1 mile. A roughly 4x4 foot board wrapped in whote freezer paper with a 9"x11" dark cardboard piece for a center hold point.

    Set the target board up and drove to the rims across the canyon to set up for the shot. I wanted to set up at some decent range so I went to where I knew I would be over 1/2 mile.

    The rifle is built on a Savage M116 receiver, basically as an experiement to see how it would perform.

    [​IMG]

    The barrel is fitted via a Rem 700 so the Savage Barrel Locking nut system is removed. Makes for a much cleaner looking rifle in my opinion. The stock is a factory Laminate which I repillar bedded and opened the barrel channel to float the #6 contour 30" barrel.

    The scope is the great Weaver 4.5-14 Tactical Mil-Dot which is my personal favorite big game scope for hunting out to 1000 yards.

    The load was the 169.5 gr ULD RBBT Wildcat loaded to 3300 fps with 100.0 gr WC872. This is a relatively mild load as 3400 fps is easily reachable but there is really no advantage at long range.

    [​IMG]

    This is the view of the target board at 930 yards.

    THis test was to see how the drop chart matched up to actual bullet flight as as I am preparing for a sheep hunt I wanted to shoot from a hunting position so I used a Harris bipod and a small rear bag and shot in the prone position.

    I set up a ranging rock just to the left of the target board to shoot at before I went for paper.

    I ranged teh target with the Leica 1200 and got three readings of 930, 929 and 930. The closest range I had on the drop chart was 920 yards which listed a hold of -4 1/4 mils dots for this range.

    As this is a big game rifle I have it set up to use a fixed zero and then use the mil-dots as multipul reference points at different ranges. The rifle is zeroed at 275 yards with the main cross hair and the bottom post was listed a as a dead on hold for 1000 yards.

    The wind was very light but there, about 2 mph so I lined the vertical stadia on teh left side of the 10" ranging rock and took the 4 1/4 mil hold and let the first shot fly. The bullet landed on the bottom edge of the rock dead center. I was happy. That would have been a very dead ram.

    I loaded a second round and raised my hold just a couple inches on target and at the shot the 10" round sandstone rock crumbled into dust. I was very happy.

    I let the rifle cool totally and thenlined her up for a three shot group on paper. To took the same hold that the drop chart listed and fired the first shot. I could see dust boil up from behind the cardboard center, I knew I had a hit very close to center.

    Loaded shot number two and settled in. This time the trigger go away from me a bit early but I still say dust fly from behind the rock.

    On shot three I concentrated better then shot two and again saw dust roll out from behind the center board.

    I loaded up and drove back to the target. I was confident that I had two shots well within a kill zone on a sheep at this range. The second shot may have dropped out.

    As I walked up to the target I was very pleased to see shots one and three within 1.5" and on the right center part of the cardboard!! Shot two had dropped out of the group but not nearly by as much as I was expecting.

    [​IMG]

    The total group was just over 5.5" ctc which from an 11 lb rifle ready to hunt, is not all that bad.

    The best thing is that all five shots taken would have easily landed on the front shoulders of a mature ram at this range.

    The data used for the drop chart was 3300 fps with a B.C. of .740 for the 169.5 gr ULD RBBT .277" Wildcat Bullet.

    I thing she is ready to hunt with. Will report on the hunt when we get back.

    Good Shooting!!

    Kirby Allen(50)
     
  2. ss7mm

    ss7mm Writers Guild

    Messages:
    3,707
    Joined:
    Jun 11, 2005
    Kirby:

    Looks like you're more than ready to go hunting. Also looks like the 270 AM is more than up to the job of taking an animal at extended range. Great post and pictures. Good luck on your hunt. Remember lots of pictures. Now you just need to work on making the hole in the barrel just a little bit bigger.
     

  3. Varmint Hunter

    Varmint Hunter Well-Known Member

    Messages:
    2,519
    Joined:
    Dec 26, 2001
    Fiftydriver

    Very impressive, and with a max optical power of just 14x. Looks like those sheep are in big-time trouble. /ubbthreads/images/graemlins/grin.gif

    Good luck.

    VH
     
  4. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    Dick,

    Its coming my friend, its coming. With the performance of the 270 Allen, the next step almost seems unimaginable, BUT, I assure you there will be another level of performance coming as you well know!!!

    Kirby Allen(50)
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    Varmint Hunter,

    I have always found the Weaver 4.5-14 Tactical to be one of the clearest scopes I have ever used. This may just be to my eyes but all my customers say the same thing when they look through them and then generally buy one.

    Problem is they have been discontinued so I am buying up the ones I find here and there from my distributors.

    14x is plenty for big game hunting out to 1000 yards. I have taken chucks at +1000 yards with 15x before. It can be hard to find them laying in the rocks and generally use my 20-60x spotter for finding them and then go to the rifle scope.

    For big game though, the target is plenty large enough to get a clean hold out to 1000 yards. Actually anything coyote size and larger is very easy to get a clear shot at.

    The nice thing about the Weaver is that the reticle is on the first focal plane so the reticle stays consistant with the target over the entire power range. This along with its clearity are what make this scope my personal favorite for big game hunting out to 1000 yards.

    I agree, there is a sheep somewhere that is going to get hammered if I do my part.

    Good Shooting!!

    Kirby Allen(50)
     
  6. Coyboy

    Coyboy Well-Known Member

    Messages:
    2,132
    Joined:
    Jan 30, 2005
    Fiftydriver, I'm glad you like the Weaver Tactical, gives me confidence in the two I recently purchased. I don't have any extensive range time with them yet, and have never used a mil-dot scope before. Do you usually aim with just the mils? Have you found the scope to be reliable and repetable if dialing in?

    Thanks for any info
     
  7. Buffalobob

    Buffalobob Writers Guild

    Messages:
    5,083
    Joined:
    Jun 12, 2001
    Gun looks well balanced. What is the barrel length?
     
  8. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    Coyboy,

    I will be honest with you, the Weaver is pretty good as far as trackability but there are better scopes out there if you want to dial in your adjustments for every click.

    This scope really comes into its own when using the Mil-Dot system on a preset drop chart as you can use the reticle over the entire power range and it stays consistant with the target.

    While I fully agree that using this system is not as absolute accurate as dialing in for each shot, it is plenty accurate for big game hunting with a well tuned drop chart.

    The ability to engage targets from the muzzle to 1000 yards with no scope adjuatment at all really increases your speed in the field. It also eliminates the risk of getting lost in your clicks in the field or finding yourself in a stituation where you can not engage a target fast enough to get a shot off.

    For extreme range, past 1000 yards, I would say get a NF or something on those lines, for anything out to 1000 yards on big game this scope is very hard to beat.

    IT is nearly perfect for shooting out to the 1/2 mile marker on big game.

    Good SHooting!!

    Kirby Allen(50)
     
  9. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    Buffalobob,

    The barrel is a 30" #6 Pac Nor super match. I selected this barrel simply because it was the only 1-8 twist I was aware of in .277" bore.

    I have since had Lilja tool up to build 1-8 3 groove barrels for the .277" bore.

    The Holland Break adds another 1.25" to the barrel length. Despite its long barrel it does balance suprisingly well.

    Good SHooting!!

    Kirby Allen(50)
     
  10. WyoHunter

    WyoHunter Active Member

    Messages:
    40
    Joined:
    Sep 26, 2003
    Super shooting!! Can you give me some technical background on your cartridge? Thanks! Looks like those sheep are in trouble. /ubbthreads/images/graemlins/shocked.gif
     
  11. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    WyoHunter,

    The first prototype of the 270 Allen Mag like its smaller caliber brothers the 257 and 6.5mm are based on an extensively modified 338 RUM case with shoulder blown out to min taper and shoulder angle increased to the Allen Mag configuration.

    Case capacity of these rounds based on the shorter 338 RUM case is equal to the longer RUM cases(7mm, 300, 375). In fact it is a bit more. I decided to use the 338 RUM case as the parent case because I was sick of dealing with belted cases as I could not fit the chamber as tightly as I wanted without sorting brass by belt thickness. I also wanted more horse power then the full length belted magnum could offer.

    The case capacity of the 257 and 6.5mm Allen Mags proved to limit the powder in which they can use to AA8700 and WC872. No stick powders can be used in these huge cases small bore magnums because of powder bridging issues which will cause severe pressure variation.

    With AA8700 and WC872 though they perform exceptionally well with bullet weights from 100 to 156 gr in the 257 and 120 to 169.5 gr in the 6.5mm.

    The 270 Allen Mag proved to be easier to load for and with bullets in the 130 to 140 gr range, Retumbo and H-50 BMG and any other stick powders in these burn rates worked well.

    With the heavy 169.5 gr ULD Wildcat bullets, AA8700 and WC872 are still top choices.

    I tested the 338 RUM based 270 Allen Mag extensively and was impressed by its accuracy and performance being able to drive 130 gr bullets easily past 3800 fps and the huge 169.5 gr pills to 3300 fps with top loads.

    I also found that this bore size when used with the slower burning powders could even accept more case capacity so I looked at the 7mm RUM case which is roughly 0.100" longer in the case body. WHat I did was simply deepen the chamber of the test rifle to accept the longer case and tested this new prototype 270 Allen Mag. Accuracy stayed the same, well under 2" at 500 yards but I gained at least a 100 fps with all bullet weights. The 130s could be driven to 3900 fps and the big 169.5 gr pills were clipping out at +3400 fps.

    The best part is that a 7mm RUM case is vastly easy to form into the 270 Allen Mag compared to the 338 RUM. Also there is no annealing really needed after fireforming these brass.

    [​IMG]

    This pic shows a fireformed 257 Allen Mag(left), original 270 Allen Mag prototype(center) and production 270 Allen Mag(right). You can see the increased length of the final form of the 270 Allen Mag.

    [​IMG]

    This is the original 270 Allen Mag test rifle with its unfinished stock and barrel.

    [​IMG]

    This is the same rifle but with the chamber opened up to the longer 7mm RUM version of the 270 Allen Mag with a Laminated wood stock much more suited to big game hunting and the rifle finished properly. Very classy looking rifle, can hardly tell its a Savage!!!

    [​IMG]

    Here is a oic of the big 169.5 gr ULD RBBT Wildcat Bullets. With a b.c. of .740 they are the highest ballistically performing 270 bullet out there. They are built on a heavy tapered jacket designed for use on deer size game for big game hunting.

    [​IMG]

    This certainly is not what the rifle will average but it clearly shows the potential of what this round will do even at the extremes of performance.

    I do not have the loading dies for the Allen Mags yet. Redding is in the process of buiding them and they tell me I will have them by mid to late May. We will see.

    If you have any other questions let me know and I will do my best to answer them on this round.

    Kirby Allen(50)
     
  12. 3sixbits

    3sixbits Well-Known Member

    Messages:
    398
    Joined:
    Jan 23, 2005
    Do I see partial neck turning in the pics of the last two ctgs? Are your neck dimensions tighter than normal for the .277 SAMMI in say the .270WIN? What kind of neck clearance are you looking at? What about clearance for the body how tight? Why not have your reamer maker do a resize reamer for you? Cut your own dies! If you are going to campaign a new ctg.. I would think you would want to keep the control over all. Have you been using a body reamer and separate neck reamers so far for all these ctgs,? I'm tiring to understand your goals as none of these ctgs. are off the shelf why not treat them as what they really could be. Long range benchrest ctgs. used for hunting. Or as usual maybe I've got it wrong, but it sure looks to me that a lot more could be made of all this work of yours. /ubbthreads/images/graemlins/grin.gif
     
  13. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    3sixbits,

    I am not sure I understand your comments, these rounds are designed specifically to provide BR accuracy at extreme range with bullets designed specifically for big game hunting. Have been all along. I have never promoted these are long range target rounds.

    The take the 257, 6.5, 270 and soon the 7mm Faster, Farther and Flatter then ever before.

    On the case neck question. My reamers are set up to allow no neck turning at all and to produce 0.00175" clearance on average with an unturned neck. This is for using the 338 RUM in the 257 and 6.5mm and the 7mm RUM in the 270 Allen Mag.

    The rings on the necks in the pics are from using a Redding Neck Sizing Bushing that was a couple thou to small. Does not effect performance but does leave a slight mark on the case necks.

    Non of my Allen Mag reamers require any case neck turning at all as again they are designed for the big game hunter not BR shooters. They only shoot like BR rifles /ubbthreads/images/graemlins/grin.gif!!!

    The body dimensions are as tight as youcan get them to work with the variances allowed by Rem brass. They are tight bodied chambered I assure you. It took several go arounds to get these dimensions where we wanted them working with the reamer maker, Redding and myself but we have designed a very quality min spec chamber that will provide extreme accuracy, very long case life even with top end loads and still allow use in the hunting field as again these ARE big game rounds first and formost!

    On the die front, The cost involved in purchasing another custom sizing die reamer is the full price of a chambering reamer or in this case +$200. Plus I would then need to purchase die blanks and then pay to have the dies properly heat treated.

    I worked with Redding and their charge to develope tooling for these new rounds was less then the envestment I would need going your way, believe me I checked everything out.

    Also, Redding will not list these dies and I will be selling them and having them in stock ready to ship with the rifles as well as the Wildcat Bullets used in these rounds as well. The entire package will be ready to ship, rifle, brass, bullets dies, directly from me.

    You are correct these are not exactly off the shelf cartridges or rifles, they are custom rifles offered only though my shop. As such if you order a rifle all componants will be offered and available though me so in a way they are off the shelf.

    Perhaps I am not understanding your comments, what more could be made from all of my work?

    Kirby Allen(50)
     
  14. 3sixbits

    3sixbits Well-Known Member

    Messages:
    398
    Joined:
    Jan 23, 2005
    Thanks for the quick reply, the fog clears a little more. So the exercise was to avoid neck turning the crap Remington brass, that makes a lot of sense! I agree that you can't make a silk purse from a sou's ear, if that was your thinking? So then will the sizing dies (from REDDING) be bushed? From my end, I look for the best brass to have the reamers made from. I guess the market that you aim at will not stand for neck turning for the most part, with Remington brass it would not make much sense anyway. I guess that really answers my other question also, The sizer dies will not be bushing type as most people will feed from the magazine and light neck tension would not be practical. Thank you sir for the run down on your system, I think you are indeed on the right tract. /ubbthreads/images/graemlins/grin.gif