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APS 338 Raptor, R&D early results

 
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Old 08-25-2013, 02:03 PM
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APS 338 Raptor, R&D early results

Well, this has been a long time coming and I know there are lots of guys on here that have been patiently waiting to see some results. I have had some serious headaches with dies, reamers and brass for this new cartridge. Its been a hard fight for over a year now but things are STARTING to come together. Still have a couple issues to clear up but at least we are actually able to get bullets in the air and do some full pressure load development.

I have not even taken any pictures yet of anything, just spent the morning doing some velocity testing to see what the 338 Raptor will do with fully sized brass.

First the rifle specs:

APS Raptor LRSS
Single shot
Mcmillan A-5 fully adjustable stock
29" Lilja Raptor LRSS custom contour barrel (would have been 30" but had issues)
1-10 twist
Medium PK muzzle brake
Bead Blast matte finish
Timney match trigger
Leupold Mk4 FFP 6.5-20x 50mm TMR reticle
4 NF Ultralight tactical rings
Also want to mention that the 338 Raptor will be available in two neck options, tight(neck turn) and standard. This rifle is the tight neck just because I wanted to see how the brass would handle neck turning.

The 338 Raptor also uses a conventional throat with leade angle of conventional specs so nothing special there, just old fashion conventional design.

The rifle was supposed to have a full 30" barrel length which is standard length for my Raptor LRSS rifles but the muzzle was slightly belled for some reason so I had to cut the muzzle back an inch to clean up the muzzle to proper bore diameter. Not a huge issue but would have liked a full 30" for the added 15-20 fps without any more stress on the brass.

Again, this was velocity testing only at the shop. Tested four different powders, H-50BMG, RL50, WC860 and US869. With my test brass FL sized and neck turned for a neck thickness of 0.010" and trimmed to length, I started with H-50BMG. Again, this brass is fully formed, correct headstamped brass made by Bertram. NO FIREFORMING needed of any kind.

Load specs that were static are:

Conditions were roughly 80 degrees
Fed-215 primer
4.340" OAL (Ya, the Raptor is made for a single shot platform)

With H-50BMG I started at 120 gr and worked up from there. Here are the velocity results with this powder:

120.0 gr............................3055 fps
121.0 gr............................3069 fps
122.0 gr............................3081 fps
123.0 gr............................3098 fps 100% load density
124.0 gr............................3128 fps
125.0 gr............................3141fps
126.0 gr............................3158 fps Crunching powder more then I like

With H-50BMG it appears that around 3100 fps should be considered about max out of this 29" Lilja. Now, my design goals for the 338 Raptor were to split the difference between my 338 Allen Xpress (3000 fps) and the 338 Allen Magnum (3300 fps) with the 300 gr bullet weights. So, my velocity goals for the 338 Raptor are 3150 fps with a 300 gr bullet weight in a 30" barrel length. First powder out of the box got very close.

I knew however that H-50BMG is a very bulky powder and in previous testing I ran out of case capacity sooner then I expected. 3100 fps was about what I was expecting to see but I did get a bit more pressure then I was expecting with a slight ejector ring on the case head at anything over 3100 fps.

Next powder up was RL50. I had great hopes for this powder and so far its performed pretty well. This is a very dense powder and allows a lot more weight of powder to be crammed into the same volume!!! Same specs are previous test, here are the results.

120.0 gr......................3021 fps
122.0 gr......................3048 fps
124.0 gr......................3074 fps
125.0 gr......................3100 fps
127.0 gr......................3137 fps
128.0 gr......................3167 fps
129.0 gr......................3182 fps
130.0 gr......................3205 fps slight ejector ring Max load
131.0 gr......................3244 fps Ejector ring to heavy for my liking

I was very happy with these results. There was a slight ejector ring at the 130.0 gr load level but I suspect at more conventional hunting temps, this will be a very comfortable load right at 3200 fps. Still, I really liked the 129.0 gr load, very comfortable, just a ghost line of an ejector ring and still +3180 fps out of a 29" barrel length.

Next up was WC-860. This is a surplus powder that is very similar in burn rate to AA8700 and the old H-870. Lot to lot its burn rate can vary a bit so you have to do some load development testing to find out the burn rate you have. That is why it costs so much less then commercial canister powder. One of the main drawbacks with this powder is that its a ball powder and tends to have some velocity variation with wide temp changes. This is certainly a concern if you hunt in a wide range of temps. Me personally, where I hunt, its rarely much more then a 30 degree temp change over my shooting times and generally less then 20 degrees as most of my hunting is early morning or late evening so temps tend to be pretty consistant. If you accept this issue and plan for it, this is a great powder, along with WC-872 and WC-578. The benefit of ball powder is its lower burn temp and very easy on throat wear, well, compared to conventional stick powders. Its also produces an extremely high load density allowing you to get a lot of powder in a give volume and never a worry about powder bridging!!!

Anyway, here are the results:


125.0 gr.........................3118 fps
127.0 gr.........................3145 fps
128.0 gr.........................3166 fps
130.0 gr.........................3191 fps
131.0 gr.........................3210 fps
132.0 gr.........................3239 fps Slight ejector ring
133.0 gr.........................3255 fps To hot, heavy ejector ring

Very happy with these results, 3200 fps is very comfortable with WC-860 with a bit of room above that for some added cushion of safety margin. Was a bit surpised that the velocity increases with the Raptor has been relatively low per grain but that is not unusual with a case of this capacity. Smaller capacity chamberings will generally show much more FPS per gain of powder increase. That does not matter much at all to me, just tells you the big displacement takes its time to get to where its going and it makes it easier to read pressures when velocities are jumping 20-25 fps at a time instead of 50 fps per grain as you work up.

Next up and final powder tested this morning was Hodgdon US-869. Again, very similar to the surplus powders. A bit better at velocity consistency over temp changes but still not quite as good as the best stick powders. Here are the results.

125.0 gr.........................3128 fps
127.0 gr.........................3151 fps
128.0 gr.........................3174 fps
130.0 gr.........................3206 fps
131.0 gr.........................3228 fps
132.0 gr.........................3253 fps slight ejector ring
133.0 gr.........................3275 fps To hot, heavy ejector ring

US-869 showed a slight increase in velocity for same powder charge compared to WC860. For all intent and purpose, they are pretty much the same. Best top working loads look to be in the 3210-3220 fps range in this 29" barrel length.

All in all, very happy. Again, my velocity goals for the 338 Raptor are to split the difference between the 338 Allen Xpress and 338 Allen Magnum in a 30" barrel length. With three of the powder tested, RL50, WC-860 and US-869, 3150 fps is a piece of cake and a VERY comfortable load pressure wise.

With the Ball powders, 3200 fps is fully practical with a 300 gr berger out of a 29" barrel length. Very happy.

I am very curious what would happen if I put my hybrid throat in this rifle just to see what it would do. IF the results were consistant with my other wildcats having the hybrid throat compared to conventional throat, I believe the Raptor will allow 3250 to 3300 fps velocity ranges in 30" barrel length. Still, my main concern is throat life. The Hybrid throat design offers dramatic velocity improvements in my 338 Allen Xpress and 338 Allen Magnum but at an expense of throat life. ITs not as huge of an issue with the 338 Allen Xpress with its 100-110 gr powder charges but when you put the Hybrid throat design in the 338 Allen Magnum with its 140-150 gr powder charges, you can eat a throat pretty quickly. I suspect that along with the Allen Magnum, the Raptor may also see issues with premature throat erosion but I may have to order in a hard cut rifled barrel and test it just to see.

3300 fps in a conventional sized rifle with a 300 gr berger would be something special for sure. That is basically my 338 Allen Magnum accuracy load in a conventional Lapua sized receiver......

Much more testing to come. I am trying hard not to want to push things to hard. My design goal was 3150 fps in a 30" barrel length and it appears this is very practical with the several powders used. May be wise just to be happy with meeting my goals and leave it there.

Will get some rounds loaded up for long range testing and will get some pics of the rifle and the 338 Raptor when I do that sometime this week if I can get up to the range before temps break into the 90 degree range!!!

Sorry for no pics but so far, the Raptor seems to be producing what I expected it to do. As mentioned, still have a couple minor issues that need to be corrected and they are in the process of being corrected but all in all, good start.
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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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  #2  
Old 08-25-2013, 02:46 PM
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Join Date: Apr 2005
Location: Alaska
Posts: 3,491
Re: APS 338 Raptor, R&D early results

Quote:
Originally Posted by Fiftydriver View Post
...I am very curious what would happen if I put my hybrid throat in this rifle just to see what it would do. IF the results were consistent with my other wildcats having the hybrid throat compared to conventional throat, I believe the Raptor will allow 3250 to 3300 fps velocity ranges in 30" barrel length. Still, my main concern is throat life. The Hybrid throat design offers dramatic velocity improvements in my 338 Allen Xpress and 338 Allen Magnum but at an expense of throat life. It's not as huge of an issue with the 338 Allen Xpress with its 100-110 gr powder charges but when you put the Hybrid throat design in the 338 Allen Magnum with its 140-150 gr powder charges, you can eat a throat pretty quickly. I suspect that along with the Allen Magnum, the Raptor may also see issues with premature throat erosion but I may have to order in a hard cut rifled barrel and test it just to see.

3300 fps in a conventional sized rifle with a 300 gr berger would be something special for sure. That is basically my 338 Allen Magnum accuracy load in a conventional Lapua sized receiver......
Interesting read.
Kirby, you ever melonite treated a barrel to compare throat erosion with your Hybrid throat to that of throat erosion on barrels you've experienced without melonite treatment?
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  #3  
Old 08-25-2013, 03:04 PM
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Join Date: Jun 2004
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Re: APS 338 Raptor, R&D early results

Nope.

Every barrel maker whos barrels I use has told me directly that any barrel treatment process they do not offer will void any warrantee on their barrels. As such, I have no interest paying for a replacement barrel in the rare occurance that something is wrong with the barrel. It does not happen a lot but it does happen and barrels do need to be replaced from time to time and I do not like the idea of having to replace a $500 barrel blank if something is wrong .

Now, the customer can do what they want with their barrel and I am sure it would increase barrel life with some of the treatment processes out there. I have tried some of them and some work, some do nothing. I tend to keep things simple in my shop.
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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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  #4  
Old 08-25-2013, 03:08 PM
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Join Date: Nov 2008
Location: Nelson, New Zealand
Posts: 289
Re: APS 338 Raptor, R&D early results

Great results Kirby

I was wondering how you were getting on with this project.
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  #5  
Old 08-25-2013, 03:12 PM
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Re: APS 338 Raptor, R&D early results

Its been slow going and still have a few issues to attend to but getting something going anyway!!!
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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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  #6  
Old 08-25-2013, 03:32 PM
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Join Date: Nov 2008
Location: Nelson, New Zealand
Posts: 289
Re: APS 338 Raptor, R&D early results

Quote:
Originally Posted by Fiftydriver View Post
Its been slow going and still have a few issues to attend to but getting something going anyway!!!
Yep it is the little things that pop up out of no where & you sit there where did that come from ?

Sometimes it goes just right & sometimes not so much

The joys of wildcatting & pushing the envelope
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Old 08-25-2013, 03:37 PM
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Re: APS 338 Raptor, R&D early results

Ya, always issues but there have been more then the norm this time around, as you said, just part of wildcatting.

Biggest issue with the 338 Raptor will be brass supply, have to see if Bertram will be able to work with me without requiring huge brass orders. We will have to see what happens.

No matter what, got to get this one on the range and testing done to see what it will bring to the field. So far, I think things are looking pretty good.
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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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