Sierra Match King 77 Grain HPBT (223)

sleddogg

sleddogg

New member
Guys - Need help, as all I have is the old Sierra manual. The 69 grain SMK is designed to fit into an AR mag, the Sierra manual states the 80 grain SMK is not designed to do so.

Is the Sierra Match King .224 (223) 77 Grain HPBT designed to fit into an AR mag??

Thanks, Sleddogg
 
Yes, it does. I seat it on top of 24Gr. of Varget (work up slowly) & for my RRA 24" up to 24.5. I seat it to just clear the mags & the RRA will group 5 of these into less than 1/2"!!
Also, just to be official, the new Sierra Manual says you can also.
 
nomosendero - hey thanks! If its not too much trouble, what do they list as min and max charges for WW748, and RL15?

Anyone else shooting the 77 SMK, love to hear your loads also.

Thanks again /ubbthreads/images/graemlins/wink.gif
 
What twist rate do you have in your AR? 77's may not work well in some 1 in 9 twist barrels. Best to have a 1 in 8.
 
Steve, its a RR NM, and its an 8 twist. Shoots 69 grain SMK very well, so I'm gonna try some 77's since they will load up in the mag.

All loads welcome for heavy bullets, Thanks.
 
Sierra is using a Colt with a 20" tube with their data.
They show 23.4 Gr. of WW748 as max., but vel. is low at 2,500FPS. They show Varget max at 23.9 Gr., I go up to 24.5
with no pressure signs. They show H4895 with 23.6Gr. max at
2,600FPS & they show TAC as the fastest with 24.0Gr. max at 2,750FPS.

In the Hodgdon 2006 Annual, the following did the best:
24" barrel
All the Max charges
Varget-23.7 Gr. at 2,737FPS
BL-C(2)-25.5 Gr. @ 2,738FPS
H335- 22.6 Gr. @2,738 FPS
H4895- 22.6GR. @ 2,727
Benchmark 22.8 Gr. @ 2,763FPS
H322- 21.8 Gr. @ 2,721FPS

I have had best results with Rem. 7 1/2Match & Fed. Match primers.

Sleddog, out of what I have read concerning the 223 with the 77Grain bullet I would try Varget, Benchmark, H4895 &
Tac, in that order, but all would be great choices.
I have seen more people using Varget with this bullet than any other, but for a source that kicks butt with H4895 as well as data for other rounds go to www.geocities.com/graymist44
It goes without saying to work up slowly.

Hope this helps.
 
WW 748 works great with bullets up to 70gr but gets real twitchy with anything heavier. It tends to get sudden large pressure spikes. I do not think it is safe with the heavier bullets.

Jack
 
Been loading my Sierra OTM 77's over 23.3 grns Ramshot TAC with CCI small rifle mag primers. Seems to be a load my 1-7" twist barrell likes. Regular rifle primers didnt seem to make a difference in laod so Im using the mag's cause I have a lot of them onhand.

Tried 748 but didnt like the results, although its my powder of choice for 52 grn HP's.
 
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