Sunday, June 7, 2015

Walking Varminter part #4, The perfect Round

The rifle actually stopped copper fouling between 40-50 on the single shots.  I no longer needed to use Sweets to get the copper out.  The copper would come out with the brushing and powder solvent.   After a couple three round break in groups it cleaned just as quickly.  I needed to move up my load development as I had anticipated while I was doing the final barrel break in I could load up some test rounds.   I know I will at least try the Nosler Ballistic tip, Sierra BTHP/Blitz, Hornady V-Max/A-Max, Barnes Varminator, and of course some FMJ’s.   The bullets will weigh from 40 to 55 grains.   I will shoot a lot of different loads, but I will know what the gun likes and doesn’t.  I expect before I am done to possibly have tried over 100 different loads if not more.  If I am lucky I will have it dialed in with less.  I go into it expecting to try a lot of different bullets and loadings.  I use brand new neck sized brass with every shot.  I keep all brass segregated from here on out by number of times fired, how sized, and how many times sized.  I also start with a three round fouled bore and fully clean every 35-40 rounds.  I let the barrel cool to the same temperature before firing the next series of rounds.   These are the fun days because I get to shoot a lot of different guns waiting for the barrel to cool.  I will also do load development with other rifles and handguns at the same time to allow barrel temperatures to stay the same. 

My goal for this rifle is .25” average group size or less at 100yds for 5 shot groups and the maximum will be .5” for three shots.  I measure the groups with a caliper, and don’t use the change in my pocket or finger size for measuring.  

I check cartridge OAL with every different bullet and start them .005 off touching the lands.  I load each bullet with 4-5 different powders, three different weights, and three different primers.  Every round is Chronographed, and I increase the powder charges until I hit max pressure or groups expand.  I take the best three groups with each bullet and start adjusting the load in small increments.  I start adjusting bullet seating depth with the best powder load by .002 closer to the lands.  If I have to I will start backing the bullet away at the same rate, but typically guns will shoot better the tighter the tolerances are.   I am tuning the load to the barrels harmonics.  By doing this you will be surprised with how accurate a factory rifle can be.  I also write down every detail of every load and save the information not only for this rifle but for future rifles.  There are certain loadings that consistently shoot well from rifle to rifle.  

I just finished up the first 110 loads and I am out of brass and some bullets.  I can not find any brass or certain bullets so I’m stuck for a while.  A bad time to need shooting supplies even for a varmint rifle.   I predicted a Savage would be accurate, and this rifle is accurate and fast for a 22” barrel.   I have barely started on the 55gr bullets, but it is showing a noticeable preference for 40 and 50gr bullets.   For the 40 and 50 grain bullets I ended up just above .6” for 3 shot groups out of 80+ different loadings!   Like most guns the absolute most accurate loads are not at maximum velocity, but I have several very fast loads to choose from under .3”.  I think +4150fps 40gr, and +3900fps 50gr shooting under .3” with no pressure signs is fast, and should put the hammer on varmints of any kind. The 55gr bullets are opening up in group size but I’m very early with them.  Now to get some more brass and bullets so I can finish preliminary testing and start fine tuning the best loads.      

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