Further notes on my ar 15 accuracy search, 20 inch shielen upgrade barrel 1-8 twist..
With an aproximate 20 degree increase in temperatures ive gone to a redo of my load with 69 gr speer match king..( Keeping my old 20-30 degree results for next winter of course) I may have to map every 20 degree variation thru out my montana weather cycle. I gone to varget which is a hodgdon extreem powder that somwhat resists temperature changes..Hopefully i can get a wider temp range and accuracy.
this reworking of the load helped get my groups back in order quite well.. I was having a problem with temp change AND worn out cases again.. 7 firiings left me with half of my necks split.. Im keeping track of firings and it may be 5-6 fireings before i have to throw out the cases. A split neck seems to raise holy heck with groups..(duh)
Ive rigged up a sloaped stock design simular to a modern wood stocked Usa rifle, and it allows me to slide the gun forward into the correct target position so my bag and shoulder pressure stays constant. the sniper flat bottom stock design did not suit me for groups and repetivive shots.. the bag would compress with each firing and need to be fluffed back up with each shot causing time and dissimular bag pressures..
A shooter friend who shot an ar in viet nam said that i should put no pressure on the pistol grip, that is torque or shoulder pressure from that point.. At this juncture i must agree. I form a circle with my first finger and thumb and tighten the circle to fire.. It seems, for me the way to shoot this rifle for the most accuracy.. Im using a bipod in the woods, sloaped stock as i said, and about 6-8 pound pressure on my shoulder with my left hand.. were not dealing with alot of recoil here.
As in earlier post follow sierras published reloading book recomendations for neck pressure and powders..
In the field the scope height causes cant problems. the terrain can totally fool me as to what is level.. the scope sits about 2 3/4 inches above the bore becouse of stock design and this is very detrimantal to first shot accuaracy when the rifle is not level.. So i bought a string level that was level, check by putting on a surface at the store and reverse direction on the level and the bubble will set in the same place if it is level. I put the level in front of the scope on the picitiny slots.. (the level is 8 sided so it sets there fine..)
The temperature change and split brass snuck up on me and i found my self blaming the usual culprets.. Barrel nut improper tension, gun joints loose ( i did buy an accuplug from brownells, and i cant tell if it helps or not, probably some) its nice the upper and lower are nolonger sloppy.... Barrel length (shortness is at blame when im having trouble, and any mechanical thing imaginable, when all the time it was my inempt loading abilities not watching temp changes and brass degredation.. (again
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first shot problems plaged me quite a bit, so i dont do a complete degreasing after every shoot..
After three times out with about 20-30 rounds each fired i degrease with breake free, brush on moble one with a small paint brush on wear points,, I started using moble one on the colt .45 when extremm cold weather was a concern. Its the spliperiest thing ive ever found and used by alot of intence officers in extreem conditions.
I then use white lithium grease on the places the bluing is worn off, and the gass rings.
On the second and third time out i clean the barrel and put a little more moblil one on the gas rings and a slight amount on the wear points.. this has been giving me better first shot accuracy, except for after degreasing and complete cleaning.. Im still learning these points..
Im finding these guns are different than the modern bolt action, but not neccesarily Inaccurate.. They are different, requireing dilligence to accomidate them..
last time out i hit the gopher block at 100 yards first shot (quite windy day). a gopher block is a 1 1/2 by 1 1/2 by 4 inches.. piece of pine.
then had to sight in the new load for left and right at 200 yards and hit the gopher block at the third shot,
After sighing in better left and right, the gun hit the gopher block effortlessly at 300 yards.. at 400 yards the gun, level, load, would not cooperate in 10-20 mph wind at all...
Ive noticed that very few bullets that fit the clip and overall lenght requirement for accuracy, And are of sufficent quality.. vmax 55, speer, bullets have poor repetibility in bore diameter distance to the rifling.. Especially box to box.. One vmax box change had an aproximate .020 ogive lenth diffence.. the boxes were consitent, but if you just used the same setting on your seater and started loading you would not have very good luck with that.. sierra and berger seem to be quite adequate.. Ive not worked with nosler much, and will probably not unless the sierra 69 causes problems, which it doesnt seem to be probable.. I havent found a berger that will fit my overall lenght requirements to fit the clip, and they dont make a hunting version of the 22 bullet line that im aware of.. Im told the sierra matchking front end will comeapartwhich is what i want for shooing in the field.. ,. Dave
