I love shooting irons on a bright, but overcast day. No glare, but enough light to really pick up the front sight and see the target too.
Nothing wrong starting with 5.56 at 100yd.
I started with bigger target, say 3moa. No need to spend money to buy targets. A divided printer paper works great for me. 1/4 is about 4"x6" or 4moa at 100yd. 1/8 is 3moa, 1/16 2moa, 1/32 1.5moa, etc.
There is no time limit on the challenge either. Enough time between shots would require re-reading the wind though and hence more challenging.
There is no restrictions on the gun configuration either. But making it too fancy or field impractical probably would loose its meaning. I favor prone with front rest or preloaded bipod, plus rear bag.
Would be nice to have a spotter. But my buddy has been sick so I have been shooting alone mostly. A longshot camera is my buddy.
-TL
Iām going to clean the hell out of our Rem 700 5R barrel. Then foul it in a little, let it cool off, and then give my best 10 round group.
If I can stand to do this more than once, Iāll try the Tikka .223 bolt gun too.
I donāt expect to stay sub MOA, but Iām excited to try.
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Found some 55 gr VMAX on the bench. Going to use XBR and Wolf Primers.
Also planning on some 77 gr Nosler CCs. Iāll try 10 of each.
Looks like a little wind this weekend, but should be manageable.
We shot the super challenge today at 100 yards. I went first on a truly clean cold barrel Rem 700 5R with the VMAX load above and watched the barrel settle in, but didnāt get sub MOA.
First round was the flyer out left.
Pappabear cleaned up with the Geissele 16" Super Duty that has an ATACR. Same Ammo, cold but not clean barrel.
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Thatās damn good shooting though, both of you.
Good shooting indeed. Was the red diamond the target intended? As per the terms of the challenge, all 10 shots must be on target though.
Cold bore shot is funny. It actually doesnāt have much to do with temperature. I donāt clean the bore after each use. My ar10 in .243 win consistently shoots the 1st shot 1.5 - 2 moa to the left. Waited an hour to let the barrel cool down and shoot again. The 1st shot doesnāt shift. Wait over night and shoot again. First shot to the left again.
-TL
Yep. I was going to shoot 5 rounds to foul the barrel, but I also wanted to watch the progression, so I rolled the dice on the clean bore.
The Geissele barrel is outstanding, but finnicky as hell. When it gets dirty, POI walks down 4 inches and right 2 inches. We re-zeroed it one time, then cleaned the barrel, and the POI was back to itās original spot. Strangest barrel Iāve ever shot.
It is likely driven by different MV. The ar10 I have, the first shot after resting at least 24 hours is always 3% higher. It takes about 3 rounds to settle. MV from a clean to fouled bore could have very different MV.
I map my cold bore shots and adjust the hold accordingly. Much better chance to be on target for cold bore shots. In reality for hunting and combat, thatās what counts. You donāt necessarily get to walk your shots on target. A tight group off target means missing the target consistently.
-TL
Thatās a good point, and makes sense. A barrel should theoretically expand a little after heating up. So a cold barrel velocity pick up makes sense.
We really ought to map our cold bore shots like youāve done.
There are different schools of thought. The way I see it, temperature doesnāt seem to be the major factor. I let my rifle rest for an hour, long enough to cool down. It does NOT have the cold bore shift. But it shifts if I let it rest overnight. The theory is the condition of the fouling surface in the bore. The long rest let the carbon lose moisture and harden.
Anyhow, I recorded more than 10 samples set firing from cold fouled bore (rested over night). The average of the data sets gives the shifts for the first 3 shots. Usually I only adjust for the first shot; hold 1.5moa to the right. I donāt dial but use the reticle to hold.
-TL
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Sounds solid. I shoot with Pappabear, here. And thereās no telling what rifles heās bringing out. Itās doable, but weāre pretty disorganized.
Life is simpler when you master one or two rifles.
Not 55gr 5.56, but 7mm SAUM on ar10. It is my new toy. First attempt to meet challenge with it.
Fired 12 rounds from fouled cold bore. 150yd. Wind calm. Prone. Blue square is 1.5"x1.5". Dots are 1" apart. 8 hits. Group is 0.7moa R50 and 1 moa R90.
-TL
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Nice! I still have small handful of the VMAX load. If we get a good low wind day, Iāll see about shooting them at 200 yards.