6.5mm Allen Mag, first velocity test results.....

[Fiftydriver]

I was able to get out first thing this morning and do a bit of load development with my wifes new 6.5mm Allen Mag.

I was shooting the 142 gr SMK but will admit the rifle is designed to shoot the 165 gr ULD RBBT wildcats when they become available. I was not expecting much with the velocity potential of this round in a 30" barrel and the 1-8 3 groove barrel but I was to be suprised by the intial tests.

I was using US869 and formed Rem 338 RUM cases.

Here are the velocity results for the different loads. All velocities are an average of three shots per load.

92 gr.......................3309 fps
93 gr.......................3326 fps
94 gr.......................3381 fps
95 gr.......................3459 fps
96 gr.......................3454 fps ??
97 gr.......................3525 fps
98 gr.......................3570 fps
99 gr.......................3616 fps
100 gr......................3674 fps

Bolt lift on every load was non existant with flawless extraction. The 100 gr load showed just a slight extractor ring but thats it. Accuracy with all loads was under 3/4 moa with most under 1/2 moa but in every case where the group was slightly larger, two of the three shots were cutting each other. Generally the slight fliers were the first shot after a scope adjustment.

I was actually amazed to see all the bullets make it to the target. I kept the barrel pretty warm, not hot but much warmer then I ususally do to see if I could get the SMKs to come apart in a warm barrel. They all made it, to my surpise to be honest.

I got back to the house and sized the test cases. All the primer pockets were basically virgin tight up to the 98.0 gr load(3570 fps). At 99 gr I could tell the primer pockets were loosening slightly. Still very usible
and in the heat I was shooting in, I was very impressed. I would call this my top end comfortable pressure load which was good for 3616 fps!!

The 100 gr loads primer pockets were a bit looser yet but still usible. If one only wanted 3 to 4 firings per case, this load would still work well and at just shy of 3700 fps no less with a 142 gr bullet.

I have no idea why the SMK were still holding together, they really should not have been at this velocity, course I have not pushed one of this size and weight this fast, I suspect very few others have either!!!

I think I will load up the 30 formed cases I have with 98.5 gr which should get right at 3600 fps and get her ready for my wife to shoot at 1K some evening if it cools down.

That Defensive Edge brake works VERY well. No jump at all, no barrel vibration from to much down thrust, just a rock solid feel to the rifle when fired. Oh ya, no recoil either!!!

First test get me more then I was expecting. I wanted 3500 fps with this bullet weight and found out 3600 fps is comfortably reachable. 3650 fps if you want to push a bit harder and if you don;t mind forming cases every 3 firings or so, 3675 fps.

Still, this round is begging for more bullet weight. When the 165 gr ULD RBBTs get here I suspect she will really start running hard. From what I am seeing with the 142 gr pills, I will be looking to break 3300 fps with the 165 gr ULD RBBT.

We will see.

Good Shooting!!

Kirby Allen(50)

 

[bailey1474]

Per my wife's orders you are to stop all development on the Allen Mags. /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

 

[James Jones]

Kirby , what sort of barrel life would you expect with this chamber?
I would think that the 142 SMK at that kind of velocity should be awsome deer/pronghorn load out to 1000+yds.

could you give a closeup of Shawn's brake?

Also were this fire forming loads this that kind of accuracy?

 

[Guest]

[ QUOTE ]
<font color="purple"> Accuracy with all loads was under 3/4 moa with most under 1/2 moa but in every case where the group was slightly larger, two of the three shots were cutting each other. Generally the slight fliers were the first shot after a scope adjustment. </font>

[/ QUOTE ]
Have you tried the trick of "adjusting one click past the total adjustment, then backup one"?

[ QUOTE ]
<font color="purple"> The 100 gr load showed just a slight extractor ring </font>

[/ QUOTE ]
Would it be possible to use the macro setting on your camera to take a pic of the extractor ring. Sounds like a good safety check for mechanical morons like myself. (Or send me a couple cases with the rings with my next gun and I'll photo them).

The military is moving to the 6.8mm SPC carbine as the perfect sized sniper cartridge (.223 too small, .308 too big). Maybe we should set up a fund to have Kirby build a 6.5mm AM for our sniper boys.

<font color="purple">&gt;&gt;That Defensive Edge brake works VERY well. </font>
I want one on my next gun!

 

[Fiftydriver]

JDJones,

Two weeks ago if you had asked me that question I would have said 1000-1100 rounds but after being able to inspect the two oldest 270 AMs out there with my borescope, I have gained even more respect for the Lilja 3 groove barrels. They were in the 600 round range and there was just a slight hint of heat cracking. The throat still looked very good although it was a couple ten thou larger then it was originally.

TO be on the safe side I would say 1000-1200 rounds, but it may be more then that. IT would greatly depend on how the rifle is fired as always and cared for.

As far as a pic of Shawns brakes. Send me an e-mail or get me your e-mail and I will send you some pics. For some reason I cannot seem to post quality pics but when I e-mail them they look good.

These were formed case but I was not really concentrating on shooting real tight groups. It was hot and I was trying to get finished with velocity testing before it got any hotter.

When I paid attention breaking 1/2 moa was not a problem at all. From what I am seeing with the groups so far, I would say this rifle will play with the 3/8" range at 100 yards.

That may not seem all that impressive but remember that this is a long bullet spun very fast in a 1-8 twist and at velocities up to nearly 3700 fps. 100 yard groups will generally not be your lowest moa level groups!!!

Accuracy testing will be next. I am going to load for 3600 fps and play with seating depth and see how she does some morning when its not already 85 degrees!!

I have no worries she will hold 1/2 moa out to very long ranges!!!

Yes she will be a serious hammer to long range deer and pronghorns.

Kirby Allen(50)

 

[Fiftydriver]

B1G_BORE,

If I am adjusting a scope in a direction that relaxes the adjustmnet springs in the scope, generally adjusting to the right or up, I will turn the adjustment two moa past where I want to adjust to and bring it back down.

If I am adjusting in the direction that compresses the springs, to the left or down, I dial right to the click and leave it because the adjustments are already under constant spring tension.

TO be honest, I was not really worried about tight groups, it was hot and getting much hotter quickly so I was looking to get the velocity numbers and get finished with the testing.

I will load to 3600 fps and then fine tune for accuracy there. She will easily break 1/2 moa at 100 yards and I suspect as the range increases the moa level will hold at this level for a LONG WAY.

Kirby Allen(50)