90gr Sierra SMK .224

[Guest]

Could anyone with experience with this relatively new projectile share their experience please?
Especially those with reasonable case capacity and velocities.
Not interested in highpower reports such as .223.
I am considering using these in a 22/6mmR Imp I am building.
Would expect around 3300 fps from my 28" barrel?
Any input re accuracy; seating depth; chamber throat and expected twist rate at the expected velocities greatly appreciated.
APB

 

[brianwinzor]

aussie powder burner, What a coincidence, this aussie powder burner just got back about 2 hours ago from chronographing the Sierra 90 MK, Wildcat 85, and 100 ULD's today in my pea shooter. (22/250 AI 28) I am using a Rem 700 SA, with Shilen SS 24.5 inch 1 in 10 twist barrel, that was formerly a .224 Clark for 1600 shots.

About 2 years ago the barrel was set back and chambered for the 22/250AI, and have been principally using the 69 grain Sierra at about 3400 fps in my field loads. This velocity is a big step down from the 3850 - 3930 with the same bullet in the same barrel using the .224 Clark.

Although I realised that the 10 twist wouldn't stabilise the 85, 90, and 100 grain bullets, I chrono'd them just to see what velocity this case would achieve.

Judging from today's results, and also my chrono results with the 80 grain Sierra MK (3730 fps) in the Clark, I estimate that you should easily get 3450 fps with the 22/6mm AI, especially as you are using a 28 inch barrel.

Kirby Allen who posts regularly on this forum, recently got about 3250+ fps with the 100 grain Wildcat using a 22/6mm AI, so that should also give you a guide. I have listed below my chrono results from the "pea shooter", which hopefully may be of interest to you and some others on this forum:
Rem Cases, Rem 91/2M primer. Temperature 27C.
85 grain Wildcat ULD.(seated .010 into lands)
40.0 grains RE 22 - 2877
41.0 grains RE 22 - 3002
42.0 grains RE 22 - 3065 (Maximum Pressure)

43.0 WIN WMR - 2994
44.0 WIN WMR - 3106
44.5 WIN WMR - 3176 (Near Max/Max)
45.0 WIN WMR - 3289 (slightly above max)

90 grain Siera MK (seated to touch lands)
42.0 grains WIN WMR - 2916 fps
43.0 grains WIN WMR - 3004 fps
44.0 grains WIN WMR - 3114 fps
44.5 grains WIN WMR - 3176 fps (Near Max)

43.0 grains RE 25 - 2943 fps
44.0 grains Re 25 - 3060 fps
44.5 grains Re 25 - 3101 fps (Normal pressure, Comp. load)

42.0 grains AR 2217(H1000) - 2842 fps
43.0 grains AR 2217 - 2931 fps
44.0 grains AR 2217 - 2996 fps (Near Max, slight comp. load)

100 grain Wildcat ULD (seated .010 into lands)
40.0 grains WIN WMR - 2753 fps
41.0 grains WIN WMR - 2870 fps
42.0 grains WIN WMR - 2951 fps (Near Max, go 0.5 grn higher)

41.0 grains RE 25 - 2755 fps
42.0 grains RE 25 - 2788 fps
43.0 grains RE 25 - 2882 fps (Near Max)

43.0 grains AR 2225 (HRetumbo) - 2740 fps
44.0 grains AR 2225 - 2798 fps (Norm Pressure, comp load)

About 6 weeks ago, I ordered a Krieger 27 inch 1 in 6.5 twist which is due to arrive at the end of Jan 06. So I hope to have the .224 Clark (Mk11) in operation by the end of March, and it will be interesting to see what velocities it produces with Sierra 90MK, and Wildcat 100 and 107 ULD. Brian.

 

[reed mosser]

I too am in the process of making a 22 dasher, all I have to do is learn how to use my lathe and rechamber the barrel. My last 22 br would shoot the 90 grain sierra's at 3000 fps with 31.0 grains of varget. That was with a 24 inch 8 twist barrel. At a 1000 yards the 90 grain and heavier bullets are much easier to spot shots and work very well. a 22 dasher or 22-6br imp should push the 90's around 3200 Fps give or take. Hope this helps

 

[Fiftydriver]

APB,

The 90 gr SMK is designed for 223 class velocities. That said, the jackets used on the SMK are relatively thick for a match bullet and as such generally will survive much more velocity and high rotational speeds then other match bullets.

The Wildcats will be in this same class of jacket thickness if not a bit thicker. Today I am going to take a Saturday off and try to get my 224 AM test barrel machined and fitted. Then I will give the heavies a good testing.

I would suspect that the 90 gr SMK would be able to handle 3300 fps accurately, possibly even more but have not yet tested them to see.

Kirby Allen(50)

 

[Guest]

Thanks for such constructive feedback so quickly guys.
Kirby - I will be very interested to see your results and hear whether the 90grSMK can survive high velocities without dusting. I did not realise that this bullet was designed with the .223 in mind and possible attendant jacket issues. I have a Mike Rock barrel I waited ages for which should be very smooth internally and "tight" as he is known fior these features. I have had it ordered for ages and intended to load 75AMax thus the twist is 8.5". With a tight smooth barrel and high velocities I may stabilise the 90gr?
Kirby,as I need to order a reamer - should I gamble that the 90gr may work in this barrel or stick with the original plan of the 75AMax? The reason for choosing the AMax [BC .435] at the time was because this projectile has a better BC than the 80gr SMK. [ BC .420] and time to target shorter due to higher velocities with lighter projectile.
What throat lenght would you advise for the 90gr SMK?
Do you think this would differ much from the ideal throat length for 75AMax?
Thanks for your help.
APB

 

[Fiftydriver]

If it were me I would throat the barrel so that it would work with the 75 gr A-Max bullets and then try the 90 gr pills of you wanted to. The A-Max is a long bullet compared to a HP SMK. The 90 gr pills will be longer but not dramatically. All would work great with a throat set up for the 75 gr A-Max.

Set the rifle up for a bullet that has the best chance at working well and then test others if you like, always a good idea. Put all your eggs in one basket and the only thing you may end up with is an scrambled eggs for breakfast /ubbthreads/images/graemlins/grin.gif!!

By the way, the 224 AM barrel is fully machined and fitted to the receiver. SHould get some cases formed tomorrow. Will post pics.

Kirby Allen

 

[RMulhern]

Any info available on load data for the standard 22/250 using the 90 gr. Sierra or Berger bullet in a 1-7 twist barrel??