This morning was calm and cool. Great time to shoot. Snuck out to shoot a couple of groups at 200yds.
Since last time testing at 100yds, I am using a new lot of bullets so started over with load development, gone back to uncoated bullets (had to scrub out the moly in the bore), and having to adjust for the much warmer temps.
Figuring out that I hadn't cleaned the moly enough lead to quite a bit of irratic and inconsistent groups. A few minutes with JB bore brite and the moly is gone.
With it being cool this morning and with a cleaned barrel, I put two down the pipe into the backstop then settled in for a group using 25.9gr of H4350.
As you can see in Group A, it shot OK. Center to center of that 5 shot group is 5/8" and I know I pushed shot 5 left. Might have been 1/2". That group maintains the 3/8MOA accuracy I was getting at 100yds. This rifle shoots!
This is where a good quality scope with high mag and resolution helps. I know from the target vs the reticle, I am loosing about 1/16" to 1/8" in consistency at 200yds. Meaning that I am 'missing' the exact POA by that much. If you have a scope with poor resolution or very thick reticle and/or low mag, your visual accuity will be worse affecting your aiming precision.
This is why BR shooters are overboosting their scopes to 42X and higher and use super thin reticles and aiming dots. You want your aiming error to be smaller then your mechanical accuracy or else you cannot shoot consistently to the potential of your rifle. Using a target that matches your reticle helps alot too.
You can't hit what you can't see....
Although I am using an Extreme powder, there is always small adjustments that are needed to account for large swings in ambient temp. With the last batch of Amax in the cold, 26.2gr uncoated was the best load at 100yds.
As you can see in group B, this load is now too hot. Yes, the first two cut but the other 3 shots show clear signs of going over the sweet spot in the barrel (plus one case was a smidge stiff to extract). The new lot of bullet might also be a smidge different adding to the need for a load change. Either way, I always start over with a major component change. Good thing I still have over 400 bullets of this lot.
The load of 25.9/26.0gr will be what I shoot. Might take another peek as we get into the summer and temps exceed 25C. Maybe a drop of a couple of tenths might be needed then???
Since this is not a BR rifle, I am stopping group testing. It is certainly more then accurate enough for a coyote or varmint rifle. Testing at 200yds is where I make a decision on well a rifle shoots. If there are problems with a load or rifle, it will show up here quite dramatically.
The fact that the first group shot under ideal conditions shows it will maintain accuracy, indicates the limiting factor is my ability to shoot and dope the wind.
Now to go pound some clays way out there (no PD's here). Will post how it does at distances exceeding 800yds.
I had three 25.9gr shells left so after shooting Group B and with a pretty warm barrel, I shot the last three. You can see from Group C that the group size grew substantially with a fair amount of horizontal dispersion.
Now some of that could be because the front bag is too wide but since this load just shot a 5/8" group, the load is not the main issue - barrel heat is. Those last three shots were rds 13 to 15 fired inside 15mins.
I know that sporter factory barrels tend to walk as they heat up. Some go from accurate to spray and pray. This barrel is no exception. I didn't have time or ammo to wait to test from a cool barrel but know it would return to small groups once cooled (enough testing at 100yds to prove that to myself).
Simply put, this barrel shoots 3/8MOA accuracy until it heats up but will still maintain MOA at a pretty toasty temp - not bad at all for a factory pipe. As this will never be a high volume poodle popper, that problem is moot. Cold barrel POI have been dead on which is what you need in a coyote/hunting rifle.
Something to keep in mind if you try working up a load with a hot barrel. The results you are getting are likely wrong and a poor reflection of the potential of that barrel. Keep things cool as much as possible.
To all that have followed this little post, I hope that this will help you tune your rifles. Also, show you the potential of these rather inexpensive rifles.
For all those that sent their kind comments, thanks. It's appreciated.
Weather is warming up so dust off your toys and get out there.
Now to go put up a target and shoot some hostages...I mean kidnappers.
Jerry
PS Stay tuned for the next project rifle based off this action. A 223 sniper/F(F/TR) rifle.
