A friend on mine just sold his last 30 cal rifle and gave me 245 Sierra tipped match kings in 168gr. Does anybody have a preferred seating depth for this bullet to get me in the ball park with them. I was thinking .015 to.020 off to run a ladder with them.
Sierra 168gr tipped match king preferred seating depth
- Thread starter Lefty Trigger
- Start date
Ok, I can do that simple enough.
For me, .005 in or .005 off is a good starting point, but I also have a very, very accurate method of finding the touch point. I hate the "touch" dimension as tiny changes in bullet profile or seating stem performance can put the bullet slightly into or off the lands, skewing results due to pressure changes.
I'm not knocking what others might do, just relaying my starting point. We all have our favorite methods.
I'm not knocking what others might do, just relaying my starting point. We all have our favorite methods.
What cartridge ? I'm running them at 2.875 in my 308. They seem to run at any seat depth. I find the 308 likes anything from 2.8 + in the 168s. Heavier bullets seem more picky for me in my guns.
Yeh its a 308 Win with a 28 inch Douglas barrel. I set them at the lands but have yet to try them, thinking of giving up shooting and taking up ark building,.... might need it!
I did notice that with a few of my 308s, they didn't like jammed into the lands or even touching as much as jumping. This was with the 168s. They were SMKs and not the TMKs. They all shot the 185 VLDs better than most other bullets but liked touching lands with the heavier 185s. Seemed that I couldn't do anything wrong when using the 168s. Just didn't quite like them in the lands as much.
Don't know if this helps but I have been and still run the SMK only in my .308.... When I first bought a box of the TMK I called Sierra and they told me to back the charge down 2-3 tenths and work back up because the TMK had more bearing surface and that the TMK didn't like to jump like the SMK....
Seems odd that the TMKs don't like to jump. The Amax/ELDs love to jump. I've heard the same thing about the TMKs but fortunately haven't had that experience. Couldn't get the 175s to shoot that well tho.
I tried the 175 TMK's in my .308 and also had a hard time finding a load and jump that worked well. I've pretty have pretty much given up on them, though as I was running out of them . . . I did manage to try a different powder than I usually use (AR-Comp) got some pretty decent results. But I just don't see a big enough advantage with them over the SMK's.
I couldn't get the 175 SMKs to shoot that great either. The 168 TMKs shoot very good for me and I can move them around 2880 fps in my 308 that I hunt with. Pretty happy.
Well my normal load is with the Nosler 175gr RDF's and Norma 203B powders running around 42.7gr and velocity is right around 2650 and they shoot good for me at a .010 jam. The only reason i'm fooling around with these is because they were free so my cost is low. I'm loading them over Norma 202 powder which is faster then the 203B.
D-4297
Gold $$ Contributor
Tried two boxes of 175 TMK's , and a box of 195 TMK's in my Kelby with a 30" Brux , 1-10 . They shot best at .005 to .010 off touch , but neither shot worth using them for competition . I'm a little open-minded . I gave them a chance ....Should have just bought Berger's , and let well enough alone .
That's because the older SMKs and the newer TMKs alongside the super-heavy MKs (110gn 6mm, 150 6.5 etc) are chalk and cheese different designs. The older SMKs have short tangent ogive nose sections and gentle transitions from shank to nose; the newer models have much longer more gently radiussed noses with a sharp shank to nose junction. That is they are in effect VLD designs, and VLDs can sometimes be very tricky to 'tune'.
Noses are measured in length, curve radius (in calibres); and how 'aggressive' the junction is. The junction shape is described by the Rt/R ratio in which 1.00 = a perfect tangent and therefore very tolerant form; 0.50 is a classic Bill Knox / early Berger VLD.
The 168gn SMK has a 0.690" nose length; 7.19 calibres radius shape; 0.90 Rt/R
The 175gn SMK is .....0.710" .................; 7.0 ..............................; 1.00
The 168gn TMK is .... 0.782" .................; 13.73 ............................; 0.54
The 175gn TMK is .... 0.817" ................. ; 14.94 ............................; 0.55
So they are very different designs, not the old SMK with an acetyl tip stuck on. The upside is considerably reduced drag which in turn produces a higher BC, but at the expense of a much less jump tolerant design. VLDs generally either like to be seated to be in the lands and if that doesn't work, seated well out (40 thou' and up) and may need some experimentation to find the best position.
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