I was getting low on ammo, so I set up to reload today. A couple hundred rounds ought to do it, so I resized brass and trimmed and primed and was ready to load em up. But first I needed to see which favorite load (of two good ones) was really best. Might as well load up the best one if I'm going to so much reloading. i loaded up 10 of one load and 10 of the other and went to the bench to try them out. Both shot poorly. Hmmmm. Went to my load records and found the COAL listed as 2.26 inches for the 40 gr Nosler BT, which I had used for today's test loads. Then I measured a few of the loaded rounds I still had, and they were all 2.267 inches. Again...Hmmm. So I loaded up some rounds with my original favorite load, at 2.267, and got about a 0.5 inch group.

I guess I had previously experimented and found the longer COAL to work so well, but didn't correct my records. Oh well...

So you are saying that .007" of OAL caused the load to go from "poor" to under MOA?

Bolt gun or AR?

Bolt gun, and yes the COAL was all I changed. The load I've been shooting in the rifle is 26.3 gr of H335, and it's been a good accurate load. When I loaded them up today, the load was shooting poorly. That just didn't make any sense to me at all. I cleaned the bore, which seemed the likely suspect, but that didn't fix the problem. I worried it was the scope or maybe me. Same brass (Lapua) and same primer (CCI BR4) and same bullet. Then I measured some old loads and found the length difference.

More loading, shooting, and testing tomorrow.

I wouldn't think .007 would make much difference. The hairs on my arm are .002.I reloaded and shot some rounds for the only 223 I have, a Daniel Defense AR 1/7, tonight. I load them all to 2.260. It shoots the same POA at 100 with 65gr Gameking W/ 24.5 RL15, and 50gr Vmax W/26gr Vargett. 1/4" with the Gamekings and 3/4 with the Vmax.

Did you weigh every load of powder?

A .007" variance didn't cause that much change at 100 yards. Something else is afoot.

How could you know that? 603 did not indicate what size group the "poor" shooting load produced so it's all relative to begin with. When you're expecting half-inch groups, one inch certainly might be considered "poor."

Yes, I weighed every load of powder. So far, the only change was the COAL increase. Groups went from an inch to half an inch, but the half inch used to be the norm.

More testing/shooting tomorrow. If I'm wrong, and the issue isn't fixed, then it pretty much has to be the new Vortex Viper 6-24 FFP PST. Most all of the great shooting this rifle has done was with an old refurbed Leupold 4.5-14. I sure hope it isn't the dang scope.

I suppose that we'll just have to wait and see what he finds, huh?

I'm back from reloading and shooting again. I just drilled a nice tight group, which I didn't walk down to measure, with the reloads. I'm satisfied with the load, since it's one I've used for a few years and has been proven to be accurate.

Unless there was a problem with the scope, and it has since healed itself, the only thing that has been changed to make poor grouping turn into good grouping was that small increase in COAL. Maybe that's all it took to move the bullet into a sweet spot. It seems unlikely, but I'm seeing what I'm seeing.

Possibly my groupings yesterday were partly my fault. We all have good days shooting and those 'less good' days, but I'm really not thinking the problem was me. Oh, well...the accuracy is back. That's good enough for me.

.007" variance in seating depth, cause a load to go from 1" to 1/2".

I buy that.

Indeed. Me too.

I wouldn't have called a 1" group "poor". Maybe a bit loose.

Glad you got everything ironed out.

I suppose I wouldn't have called a 1 inch group poor, if I hadn't spent way too much on this rifle to make it shoot better than that. And, as I said, it has been shooting better than that. It's my fault, since for some unknown reason it seems I didn't write down the 'good' COAL from the previous batch of reloads. Well...I wrote it down this time.

When one of my rifles that should shoot half-inch groups starts shooting an inch, something is up. That is a 100% increase in group size, and I regard it as "poor" performance also.

I was about to feel really bad, I sold him the scope

I like that scope a lot, particularly that it's on my 223. I shoot several bullet weights, so I can dial for the bullet. I love that.

The rifle is for yard critters, which means shots up to 150 yards. And I use it for family shoot-outs for bragging rights. I hang golf balls from a stand at 100 yards, and each person gets to shoot in turn. The pressure builds as folks (guys and gals) miss or don't miss and the trash talking gets serious. It's a hoot. Reminds me that I need to get more cheap golf balls.

And, I dial the scope for the 65 gr Sierra GKs and go hunting with it.

I should mention that the college granddaughter recently suggested that we need to maybe shoot marbles, since golf balls are easy. The kid can shoot, and she's getting pretty cocky. I might need to drag out the 220 for marbles. That gun is amazing.

That figure and variation wasn't disclosed in the initial post, or I would have agreed.

We do an egg shoot where every time you miss you put $5. in a pile. At the third egg whoever made the most hits wins the pot. Small eggs at 150 yards. Never pays to miss! It never ceases to please and surprise me that people who can't shoot worth spit will continue to try.