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APS Big Boy!

One more pic:D

PB170277.jpg
 
Just to add a bit more to what Ernie has offered. We have been pretty tight lipped about this for several reasons. The design is one that I designed many years ago but never really had the correct application for until Ernie contacted me about wanting an XP chambered for this class of chambering.

The real problem to this is the stock holding up simply because the XPs recoil lug is VERY limited in contact area to the stock and generally this small area will break down. On top of that, it is not uncommon not to have the stock crack at the top of the pistol grip with even much smaller chamberings then this.

My design uses a full diameter 1.350" diameter barrel shank that has a traditional XP recoil lug in the standard location but it also uses a conventional rifle recoil lug ahead at the front of the full diameter barrel shank. THe barrel is machined and threaded at this location and a custom made stainless steel lock nut is threaded on to hold the forward recoil lug in place.

I fully admit that the original idea came from a design that Darrel Holland uses for his V-block rifle design only that he uses an aluminum V-Block with a forward recoil lug but no rear recoil lug.

My design uses two recoil lugs which effectively triples the baring surface to the stock for the high recoil energy levels of this type of chambering. Also, I install a pillar just behind the forward recoil lug and thread the barrel to accept a 1/4x28 tpi mounting bolt. The stock is bedded for full contact up to the forward recoil lug and entire receiver. The lock nut is floated as is the barrel from the the nut forward.

The regidity of this system is simply amazing compared to conventional bedding and since there is no large aluminum bedding block, there is no problem putting this design in a slim sporter profile stock so weight can be kept down dramatically, as can the dimensions of the handgun.

I decided to have the 1.350" shank fluted on the top half to drop a bit of weight as well, plus it just looks good.

I have also been working on my new Raptor rifle package. Some of you may remember that project a couple years ago that did not turn out into production rifles but I have decided to start that project up again and have been working on that for the past year and it should hopefully be ready for field testing. The new Raptor will have a new receiver as well as a rifle version of this new barrel design to offer EXTREME rigidty but with very little if any increase in weight over a conventional barrel contour.

Anyway, the hold up in accuracy testing has been the wind. Its been blowing around here for nearly the past three weeks over 20 mph. Many days over 40 mph and several over 60 mph. I have never in my 36 years remembered a stretch of windy days like this. Was very hard on hunting and a killer for accuracy testing customer rifles and handguns which are backing up waiting to get on the range. Its supposed to cool down this week so I will hopefully be able to get out and so some long range accuracy testing with Ernies XP very soon.

Recoil wise, the 225s barely kick. I know many do not believe that but its true. The 250 gr ABs are not much more but a bit more. Still extremely comfortable. The 300 gr is not uncomfortable but its a noticable jump in recoil but then again, it is a 300 gr SMK at over 2700 fps!!!

More to come soon as well on the APS Raptor rifle. This is still in the prototype stage so no orders are being taken at this time for either platform but once they are fully range testing and proven they will be available.
 
Howdy ..
A very nice piece indeed , I can totally understand the logic of that additional lug and the increased bedding area . these stocks can take a beating for sure .

But with a cartridge as big as a 338 Lapua Mag / Imp , was additional attention taken to the bolt , lugs and seats ? Those big cases with 100 grs of powder sure could raise some doubts using that XP action originally set up for the 221 fireball ...
I'm no gunsmith , but I am interested in your ideas
thanks

Ray
 
Real nice Ernie. I can't wait to hear some range reports, it must be killing you not to have it in your hands yet. ;)


You're right my .338 Lapua is a 20 inch barrel and my velocities are right with yours. With my 16 pounds of weight, recoil is very controllable with the 250's.

I'm having a .338 Norma mag built as we speak. It uses an XP action too on a McRee stock. I had the bolt made by Pacific Tool. I expect it to end up between 10-12 pounds overall weight sooooo I'm curious as to how heavy your rig is and how it reacts with 300 grain bullets. I'm going to start off using a pistol scope and then maybe move over to a rifle scope.

I went with a slightly longer barrel than yours as I'm hoping I can hit my velocity goals (300 grain at or near 2700fps) without pushing the pressure too high. I'm a bit apprehensive about using the XP action myself, but I researched it pretty well and the feeling from several smiths was that it would work just fine. I sure hope so.

Congrats again on a fine looking and I'm sure a fine shooting pistol!!!!
 
There have been many talking about the strength of the XP which really suprises me. The XP-100 was designed many years after Remington had their rifle bolt actions on the market and are made to very similiar specs as far as the bolt head and bolt lug supports in the receiver.

If you look at a Rem 700 rifle receiver, the weak link in this receiver is the bottom bolt lug support because there is relatively little steel supporting this bottom bolt lug because of the mag box window cut out.

In the XP-100, there is nothing but solid steel supporting both the bolt lugs. The bolt lugs are of the same size as the full size Rem 700 and I have found no weakness in the Chrome Moly Rem 700 for chambering the Lapua class chamberings in this receiver.

I do have a problem with the Stainless Steel M700s being chambered in the Lapua class chamberings because the bolt lug supports are stainless steel and much softer then the Chrome Moly receivers. As such, you have a higher likelyhood that you will get some set back with the stainless receivers.

To be honest, if you load the Lapua to its proper levels, both receivers would handle this fine, its when some start to push the Lapua case to its limits that you get into trouble and will with any receiver because of the extreme strength of the Lapua case.

You can not load the Lapua up to where the primer pockets just start to loosen and consider that a max working load as you will be WAY over pressure for any factory receiver, well, any receiver at all to be honest.

If your concerned about pressures, do load development with Norma 338 Lapua cases which are similiar in strength and hardness to Remington RUM cases and their primer pockets will show pressure signs MUCH sooner then the Lapua case. Then once you have your load data worked out you can go over to the stronger Lapua cases and use them for your loads.

Simply put, the XP-100 is a stronger receiver then the 700 for sure and if loaded correctly, they will easily handle any wildcat based on the Lapua case.
 
Thanks Kirby, I appreciate the detailed response. I always learn something from your posts, and now I feel even more confident in using the XP action for my .338 Norma build.

Really looking forward to the field report on Ernie's new gun. I hope the wind slows down soon!



Thanks again



Doug
 
Kirby ,
I also thank you for taking the time to answer these questions about the XP actions , I appreciate your thoughts and experience on this .....
Thanks again
Ray
 
Well my friends, today was the day. By good shooting conditions standards it was pretty bad but compared to what we have delt with for the last several weeks, pretty darn calm, only 10-15 mph winds!!! Only problem was it was 18 degrees when I got up but I decided I had to suck it up and test some rifles and a big handgun before I had customers giving up on me.

For Ernies XP used a load of 103.0 gr Retumbo under the 250 gr Accubond which proved to be a good comfortable load.

I set up at 670 yards on a lightly snow covered side hill to get the XP close to point of aim. The snow DRAMATICALLY helped me see where the XP hit at as the recoil was enough to jump it off target shooting off 12x but there was a very clear and well defined impact crater left in the fresh snow.

Took three shots to get it close and then I put a pair of shots literally on top of each other at this range. Figured it was time for some longer range. Because it was cold and I wanted to just test her at long range to see if it met standards and then let the real shooter deal with the details, I set up at 1375 yards. There was a 3/4 moa target rock that was laying in the middle of a bare snow covered bowl which was bare dirt under the snow. Impacts would be clearly seen even if I missed the actual impact. That did not turn out to be a problem though as I was able to recover from recoil at this range and see every shot land.

Took a couple shots to see where I needed to hold on the TMR reticle to get close to the target rock. Again, I was not overly concerned about hitting the rock, just wanted to get close and the actual impact in the snow would give me a much better idea of group size then actually hitting the rock.

First shot landed roughly a foot low of the target rock, dead center horizontal. I was dealing with some variable winds from right to left but at my location it was very hard to read them. Second shot was easily within 3" of the first. Third shot landed just above the first two but so close that it still left only a single crater in the snow. I put five rounds total through the XP and when all was said and done, the total impact crater was smaller then the target rock which again was roughly 3/4 moa measured off the TMR reticle. Now figuring that the actual center to center impacts were much smaller then the actual visable crater, I was very satisfied with the results. Especially considering this is a pre break in barrel and the first load I put through it.

I also wanted to test the barrel when it was warm just to make sure that bolting directly to the barrel shank would not cause any accuracy issues when the barrel warmed up. I found another target rock just to the side of the first one and shot another three shot string while the barrel was still warm. First and third again were so close it looked like same crater impact. Second shot landed about 8" to the left but I totally believe that was blown by the wind as I my right cheek felt the wind pick up just as the trigger broke. Still height wise, it was perfect. All 8 shots had no more then 5" vertical spread on them.

Put her away and am fully confident that she will perform pretty darn well in much more capable hands. These load were with the freshly fireformed brass and it appears that muzzle velocity was very consistant, if it was not, it made no difference on grouping at nearly 1400 yards.

I did not test the 300 gr SMK simply because I was under the impression Ernie wanted to use the Accubond for hunting but after reading his post here it seems he may want to go with the SMK. I have no doubt that it will perform at least as well as the Accubond in accuracy, especially when dealing with crosswinds. I have never seen an example where the 300 gr SMK would not shoot extremely well in a sound firearm and this one certainly seems to be that.

All in all, I am very happy with the end results. The XP was quite controlable on the bench. First shot she hit the brim of my hat pretty solidly but once I turned my hat around, it never came close shooting with full field of view on 12x through the Leupold 4.5-14x50mm Mark 4 LRT scope. I am sure 14x would have been just as easy. There was no hand discomfort of any kind but I did start to get a bit twitchy simply because I have not maintained practice with the big handguns and its a simple issue of hand grip control more then anything. The muzzle did not jump much at all.

My opinion was that most of the movement in the XP was caused by torquing of the handgun, something we simply can not eliminate completely with this class of chambering in this weight of XP. In all honesty, its a pretty light handgun for this class of chambering.

Anyway, she is proven to me. Will be heading to her new home in Wyoming here in the next day or so and I am sure you will hear much more about her from Ernie. Seems the double recoil lug design has worked as planned.
 
Makes Dirty Harry's look like a pea shooter. Man can you imagine the look on people's faces if you walked on the range with that BEAST. Simply gorgeous...a work of art...not surprising coming from Kirby. Congratulations Ernie.
 
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Just one word...dang.

Nice, Ernie! And way to make me feel inadequate with my recently acquired XP 7mm-08! lol
 
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