Originally Posted by
Bruce_in_Oz
If you look closely at the GP-11 bullet, and even better, at the drawings for it, you will see a very unusual feature, apart from the long boat-tail.
The ogive is of secant form and starts immediately forward of the cannelure. There is almost NO parallel bearing surface on the entire bullet.
Thus, ANY "ersatz" bullet MUST have a similar secant ogive form. Especially if you are feeding a K-31. WHY?
Unlike the earlier K-11, the K-31 has a VERY short throat, specifically designed to work with the GP-11 bullet.
The 1911 models have a LONG throat designed to work with the earlier, "torpedo-shaped" GP-90 /03 ammo as well as the "new" GP-11. By the time the K-31 was introduced, there probably was no need to accommodate the ancient GP-90 ammo.
Thus, the short K-31 throat MUST be fed with secant ogive bullets, not tangent-ogive stuff like the Sierra style.
I use the locally (Oz) made BJD HBC 155 grain, secant ogive jobs, because they WORK and I also use them in my "full-bore" .308" target rifle, in which they also work very well.
. I got a good string of 10s shooting from 300yds on the MR63 target (5.85" circle) using an old Noske 2.5X scope last match I shot in.
PM
