APS Raptor XP-100

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Fiftydriver, Aug 20, 2012.

  1. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Figured you guys would like this one. This is one of my Raptor XP-100s chambered in the monster 338 Allen Xpress which is an improved version of the 338 Lapua.

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    To chamber this class of chambering in an XP-100, there really needs to be some heavy modifications made to the factory XP-100. The XP is an amazingly strong receiver but its stock and bedding sytem are pathetically weak. As such, if you build an XP into a large handcannon chambered for something like the 338 Allen Xpress with conventional bedding, your just asking for failure.

    First thing you will notice is the odd barrel contour. This is the original APS Raptor dual recoil lug barrel contour which is currently only retained in the Raptor XP-100. As you can see there is a forward recoil lug held to the barrel with a special threaded NUT similiar to what you see with the Savage rifles. This forward recoil lug supports most of the recoil energy as the rear recoil lug that also serves as the trigger hanger has very small contact with the stock from a recoil support point of view.

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    Not only is the front recoil lug a nessesity for long term functionality, we also need to support that recoil lug with something other then stock fill material. There is a custom machined 1" square Stainless steel block embeddd into the stock just behind the front recoil lug. The bottom of this block is machined with a round stub that extends through the underside of the stock and appears to be a conventional pillar. A 1/4x28tpi mounting bolt is used through this block and mounts into a drilled and tapped hole in the under side of the barrel to securely hold it into the bedding.

    The rear mounting screw is also modified to use another 1/4x 28 tpi mounting bolt which is dramatically larger then the small factory screw. So the Raptor XP-100 uses three 1/4"x28 mounting bolts instead of one 1/4" x 28 and one screw that is about the same size as some scope rail base screws!!!

    The bedding of the receiver and barrel starts just ahead of the bolt handle notch and extends with full support up to the forward recoil lug which makes it several times larger in support area then the factory bedding.

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    SO what else is done to this big handcannon? The receiver is fitted with one of my Raptor side mounted bolt stop levers. This makes things a bit tricker to get a fired case to eject, especially one as long as the 338 Allen Xpress but its doable with some slight work on the ejection port to lengthen it by 75 thou or so.

    The receiver is also modified to use the 5, 8-40 mounting bolts of the NEAR heavy duty rail base so its about as stout as possible.

    How about recoil, well, with a clean muzzle, the 338 AX would be BRUTAL. Realize that this HANDGUN will drive the 300 gr SMK to 2650 fps with top end loads. When you realize that the Hodgdon load data for the 338 Lapua lists a top velocity of 2677 fps with the same bullet........

    Yes, thats a Nightforce NXS in the four NF tactical scope rings. And yes, you can shoot this monster with nearly full field of view without getting your forhead tapped by the scope. I tend to shoot with a very relaxed hold on these handcannons so I always shoot with a 3/4 full view through the scope but I have shot with 100% full field of view with a solid hold and never had any fear of the scope getting friendly with me.

    The big 5 port Painkiller muzzle brake takes care of all your recoil fears. In fact, recovery from recoil is good enough that I could spot my own shots at the test range at 1052 yards.

    So what kind of accuracy do these big handcannons produce. Well. It shot a few three shot groups at 1052 yards that were under 3/4 moa and one group was easily 1/2 moa.

    Yes this is a specialty handcannon but figured you guys might be interested just to see it. Not to many of them out there but they are truely special. Shooting them is comparable to the 50 BMG or 408 CT based wildcats in experience. It is an event!!!
     
  2. Joe King

    Joe King Well-Known Member

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    Figgured the break had to tame it or you wouldn't bother with it, but the muzzle blast has got to be horrendousgun)

    Very Very cool non the less:cool:
     

  3. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    For the shooter, muzzle blast is very reasonable. The long runners in the PK muzzle brake really direct and focus the escaping muzzle gases and do a heck of a job protecting the shooter.

    However, you need to make for darn sure you stay away from things to your sides and keep your spotter and spectators behind you!!!
     
  4. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    Why are you using a short eye relief scope on this cannon of a gun??
    I've shot the 300 wsm in a striker and it needs a long eye relief scope even with the savage brake. I expected either a taco type mount or pistol scope.
    Usually the rifle scopes on pistols are reserved for 223's or smaller. I even run a m8 4x eer Leopold on my 22-250.
    Just wonderin' I guess....
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Not if you use a real muzzle brake!!! :D

    Main reasons for a rifle scope over a handgun scope.

    - MUCH better vertical adjustment range
    - Much better reticle choices for long range shooting
    - Dramatically better light transmission, especially at low light
    - Much larger field of view
    - Much better image quality
    - Better power ranges
     
  6. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    You build a heck of a weapon Kirby.
    I'm partial to my 4x leopold.
    I've killed prarie dogs to 1/4 mile with 4x using a single heel bag under a striker using a 7-08. I'll be re-barreling to 6x284 on my striker when the 22-250 is worn out. I sold my other striker when the 243 barrel went south three years ago and I'm feeling the pull of 6mm again.
    If I want a 338 in a pistol I'll either go your way or a custom TC. I've played with TC and they do not disappoint.
    A somewhat off the wall question. Are you altering the loads for the short barrel at all or you just going with it??
     
  7. royinidaho

    royinidaho Writers Guild

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    May I jump in here to interrupt this conversation to say . . . . . Ob darn scene.......... WOW!!!
     
  8. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    I build custom XPs in all chamberings from 223 on up.

    I think you will find that the 6mm-284 will be a poor performer in the short barreled handguns because of its relatively low expansion ratio. There are some rules to follow to get good performance out of handgun length barrels.

    1. The fastest load in a rifle will be the fastest load in a handgun. THere is no need to go to special powders.

    2. The lower the expansion ratio, the more barrel length dependant the round will be concerning muzzle velocity.

    3. If you take the same capacity and compare it with two differnet bore sizes, the larger bore size will produce higher velocity and often times dramatically more velocity as the barrel length decreases. For example, if you take a 6-284, 6.5-284 and standard 284 Win. The 6.5mm-284 will drive a 100 gr bullet probably at least 100 fps faster then the 6mm-284 will drive a 100 gr bullet weight. The 284 Win will likely drive a 140 gr bullet nearly at the same velocity as a 6.5-284 will drive a 120 grain.

    If you want as much velocity as you can get out of a shorter handgun length barrel, step up to a larger bore size.

    I am a fan of the TC handguns and rifles for that matter but they are not nearly strong enough for the big, high performance chamberings. Even moderately powerful chamberings have to be loaded pretty conservatively or you will start to get serious case stretching in the TC. Compare that to a bank vault strong XP-100, there is no comparision.
     
  9. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    I am not 100% sure what cal it would be, the 243 wssm holds merit also, as does the 243 and 25-06 if I go encore. I've been able to get 2800 fps with the striker with 100 grain in a 243(14"), so it shouldn't be tough to do a beat that with a bit more capacity. I've got a 44 for big bore engagement to 200 yards and over that I'll use a rifle so smaller cals are what I'm looking at for the most part.
    We've noticed a rather marked improvement with pistol performance over the years by going with slightly faster powders than usual and lighting them hot, ie. a 215 in a 243. I could beat standard velocity by nearly 200 fps with v540 and not run higher than normal pressure. In a 24" barreled rifle the loads were about normal speed wise. With the enhanced pressure curve of superformance and a few of the other newer powders I could see where they would be trouble with a sub 20" barrel. With a 300 wsm pistol I'd look at rl17; it would be a hoot with 165's. I think my father is still using i4350 in his wsm pistol.
    You are correct about the expansion ratio mattering in a pistol, but not as much as Herret and some of the others thought. I'm loosing around 400 fps with my 22-250 with a 14" barrel. It'll still do 3500 fps with 45 grain factory win's and do 5 in an inch at 100yards with it. I haven't worked with it with handloads enough to care on speed as my first couple loads shot well; load development complete.
     
  10. Buttermilk

    Buttermilk Well-Known Member

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    Excellent!!!

    I like that one Kirby. :)

    I need one similar to that, but only in a puny 300 WSM or 300 RSAUM.... :)


    Regards,
    Rog
     
  11. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    This design is a bit of overkill for a 300WSM but thats certainly not a bad thing!!!:D
     
  12. Mark Mck

    Mark Mck New Member

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    Very interesting post! I've been shooting small game with my XP-100s and am interested in moving up to something more powerful and effective out past 1000 yds. One of these in 6.5 WSM or 260 Rem might be what I am looking for. :)
     
  13. mindcrime

    mindcrime Well-Known Member

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    As patient as I have been in your meticulous building of my CZ550 Safari Magnum based .338 AX, and am the owner of a stock 7mmBR XP with the addition of only a Fajen thumbhole stock; THIS XP-100 is BAD A$$!!! If I hadn't been waiting for a year and a half for my CZ, I would be extremely tempted for you to make me a matching .338 AX rifle/pistol combo! Your work is simply beautiful, honestly. I will be excited to show off my special Magnum Mauser build when it is done.....I am so excited.....you have to be getting close after our recent emails. STILL, I am leaning toward a .358 caliber for my XP build. As much as I love the .35 Whelen, a XP-100 in .358 WSM would be awesome (just no match bullets in that caliber; sucks, lol)......I'm just proud to have my own "APS Custom Build" on it's way, and can't wait to share it here on the LRHFs!!!
     
  14. esshup

    esshup Well-Known Member

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    Now THAT'S an Indiana legal handgun!!!!!!!!!!

    I love it!!

    Nice job Kirby.