I just chambered up my 28 inch 6.5 twist pac-nor barrel to a 22 dasher and throated it for the 100 grain wildcat bullets. I have reached a maxium load with 39.5 Ramshot magnum powder with a reminton primer. My problem is my primers are showing max pressure and the speed is only 2800 FPS. I was expecting 2900 to 3000 FPS. Could my problem be with the slow powder and small primer. Should I try a hotter primer, moly, or do I have a slow barrel, wrong powder, ect ,ect. Right know I am 100% load density, and have pressure. Am i out of line for wanting more speeed? I know those who are shooting 6mm dashers and 6 brx are getting 3000 FPS with 105 and 107's. I am going to try some 90 sierras too. For FPS comparsion my 22 br with a 24 inch tube would shoot 90 sierras at 3050 with 31.0 varget and little pressure. Any info,help, would be appreciated, Thanks Reed
I would say you may be a bit on the low side of velocity but not by much. Remember that the 100 gr ULD RBBT is a VERY long and heavy bullet. Th 105 gr A-Max is 1.230" in length compared to a 22 cal 100 gr ULD RBBT that is 1.300" in length. Thats a 0.070" longer bullet in a 19 thou smaller diameter bore!!! Your comparing a sectional density of .254 for the 105 gr 6mm bullet to that of .285 for the 100 gr 22 cal bullet.
TO put that two into perspective you would need a 120 gr 6mm bullet to get the same sectional density as the 100 gr 22 cal bullet. With that in mind, how fast do you think you could drive a 120 gr 6mm bullet in a Dasher or BR???
Another critical area to consider is baring surface. The baring surface on the 100 gr 22 cal bullet is roughly 0.680" in length. Compare that to roughly 0.450" of baring surface length for the 105 gr A-max and you begin to see the dramatic differences between the 100 gr 22 cal and 105 gr 6mm bullet as far as pressure and velocity potential will be concerned!!
I would say you are just about on the money. I am getting around 3400 fps with my 224 AM with the 100 gr ULD RBBT and thats with 73.0 gr WC872 behind that bullet!! TO get 3000 fps with the Dasher would be most impressive and certainly running high pressures in my opinion.
How are they shooting by the way?
2800 fps is plenty for long range shooting with this bullet. BC should be in the .600 range from best estimates.
Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.
It looks like are going to shoot well. I have only put 10 rounds down range and seems that they are going to shoot ,despite the shooter. I jammed them into the lands filled the case with ramshot and cleaned up the inside of the necks. I was very happy to see low extreme spread with out much effort. You are right about the bearing surface, the more friction, more pressure, less velcioty. I am going to do more testing, but your right 2800 fps will be all I really need. This gun will mostly be used for 500 and 600 yard ground hog shoots and hunting out to a 1000 yards. I hope the B.C is higher than .600 [img]/ubbthreads/images/graemlins/smile.gif[/img]. I might be shot for this but last year when shooting my 22 br out to 1000 the drop from my charts indicated a b.c at .600. Take it as you want. Going to do some more testing. Thanks for the response it was greatly appreciated.
RM, I agree with Kirby's comments, and believe your 2800 fps with the 100 grain Wildcat is about the mark.
I believe that it is unlikely that you will exceed that velocity significantly, as your load of Ramshot Magnum is a achieving maximum pressure with a 100% loading density.
My 22/250AI has a capacity of 49.2 grains, and recently achieved 2,951 fps with the 100 grain Wildcat ULD, and 3,176 fps with the 90 grain Sierra MK. This was achieved in a Shilen 24.5 inch barrel with 1 in 10 twist, and obviously the bullets did not stabilise.
To compare your results to mine, if I added another 3.5 inches of barrel length to my rifle to equalise our barrel lengths, it should produce another 75 fps, which would bring my velocity to about 3025 fps. This represents a difference of about 225 fps between the 22 Dasher and the 22/250AI, and is about what I would expect considering the relative case capacities.
I believe the relevance of case capacity when using the heavier bullets has been shown, when you compare my results with the .224 Clark in this barrel (25.25 inches then), which became about 24.5 inches after setting back and rechambering to the .22/250AI.
The .224 Clark achieved velocities between 3,850 and 3,930 with the 69 Grain Sierra MK, and 3,650 and 3,730 with the 80 grain Sierra MK.
The 22/250AI achieved velocities between 3,350 and 3,430 fps with the 69 grain Sierra MK, and 3,175 and 3,260 fps with the 80 grain Sierra MK.
My load data indicates that the 450 - 500 fps velocity advantage of the .224 Clark was achieved with the use of about 10.0 to 11.0 grains more of the same powder.
Hope that the above information is of some help. Brian.
I just got back from the range and am feeling much much better. After another 20 rounds and a little bit of tweaking I have found a good load. Yes the litttle dasher will hold 40.5 ramshot magnum at the base of the neck changed the seating depth 7 thousandths. Speed 5 feet from the muzzle was 2900 Fps and I finally rembered how to shoot ans shot a 3 shot group in mid .1's to .2's. I am know happy. I will also say this is my first pac-nor 3 groove and cleans up easier than any other barrel I have had. And from the other post regaurding B.C it was for the 90 grain sierra at .6, that was accurate for my drop charts. Thanks every one for you input I will post some pic's soon of my first complete build. Thanks Again