04-05-2022, 10:58 AM
...500 box of Sierra 107 SMK's arrived and started initial prep work to load & test. Measured for "touch point" in my barrel (20" BalAdv) and they averaged 1.7574" CBTO and a corresponding 2.30795" COAL. I have to admit, the Sierra's had near perfect CBTO measurements, but the tips had COAL variation ranging from 2.303" to 2.310".
I also tested just how long I could make them so that they still fit in my magazines. I ended up having to seat them to a MAX COAL of 2.269"-2.270" in order to fit in both magazines with clearance for the tips, the E-Lander being just a tad shorter than the Duramag. I tested by putting 3 empty cases in, followed by the dummy round in both left & right feed positions. I also tested by loading more empty cases on top to push the dummy round down to and beyond the curve in the magazine, which is where binding could occur. If the tip made a scratch mark on the mag, I'd adjust my seating stem down .02" then try again but on opposite feed side so if touching a fresh mark would be made.
At this COAL they will be jumping 0.04". Hopefully the alleged "jump tolerance" of the SMK line holds true with this bullet. This will put the junction of the bullets boat tail & bearing surface right about at the casings neck/shoulder junction and base of bullet right at or just below the casings shoulder/body junction. This is less intrusive into the powder column than the 108 ELD-M, 105 RDF & Berger 105 VLD. I'll be testing these with Lever.
I'll follow up once I am able to get out to test.
I also tested just how long I could make them so that they still fit in my magazines. I ended up having to seat them to a MAX COAL of 2.269"-2.270" in order to fit in both magazines with clearance for the tips, the E-Lander being just a tad shorter than the Duramag. I tested by putting 3 empty cases in, followed by the dummy round in both left & right feed positions. I also tested by loading more empty cases on top to push the dummy round down to and beyond the curve in the magazine, which is where binding could occur. If the tip made a scratch mark on the mag, I'd adjust my seating stem down .02" then try again but on opposite feed side so if touching a fresh mark would be made.
At this COAL they will be jumping 0.04". Hopefully the alleged "jump tolerance" of the SMK line holds true with this bullet. This will put the junction of the bullets boat tail & bearing surface right about at the casings neck/shoulder junction and base of bullet right at or just below the casings shoulder/body junction. This is less intrusive into the powder column than the 108 ELD-M, 105 RDF & Berger 105 VLD. I'll be testing these with Lever.
I'll follow up once I am able to get out to test.