Guru needed

[dave-t.]

OK guys I'm pretty close on one load, and am happy with two.

What is the next step to shrink this up a bit? Different primer? Seating depth?

http://www.archerytalkpics.com/gallery2/d/21649-2/Erin+09+081.jpg

I have another that strings a bit, but I can be pretty happy with the load as is.

http://www.archerytalkpics.com/gallery2/d/21645-2/Erin+09+080.jpg

And this one I don't really care to mess with. I measured it three times, and it doesn't look like it should be under .6", but honestly I'd still be a happy camper if the caliper came back with .8"

http://www.archerytalkpics.com/gallery2/d/21653-2/Erin+09+079.jpg

[dave-t.]

That top group is a middle of the road load at 48.5 grn. I also tried 48grn at the same seating depth and got a 1.8" triangle group. Primers seemed pretty flat to me for a mid range load (book minimum 46grn -max 50grn), but I am new at this.

Would it be a good idea to try to seat it a little deeper, and go up another .2-.3grn?

[Bushman]

How about a good cleaning Dave? Some years back I spent some pretty major money on a high end Shilen barrel for a new 7mm-08. After the barrel was broken in, it was about a 1.5" moa rifle. While that was always good enough for my close in deer hunting, I never thought it was good enough for what I payed for that barrel. Then I got to reading about the difference in cleaning with a powder solvent verses a copper solvent. After I used that copper solvent to properly clean that barrel, the groups went into the .75-1" range and I'm way more pleased with the rifle.

[dave-t.]

I had cleaned with Barnes Copper solvent cr-10 before shooting these groups. That top group were shots 11-14 for the day for the .257, the bottom group were shots 7-10.

The 300wm group was only shots 4-6 for the day with that rifle, and I almost stopped shooting it right then, but had another 3 loaded with the same charge to a longer oal. Shots 7-9 went around 1.3" or so. I do have to say that I was happy with the rifle as I didn't have a flat out 'bad group' with any of the 3 loads that I tried. 1.04"@71gn, .8"@71.5grn, and 1.3"@71.5grn at longer oal.

I can't imagine that it would be fouled terribly after so few shots, but it may be worth a try. I'll definitly see next time I'm out.

Also, do you clean with copper solvent after every range trip? I have not up to now, just common gun solvent and rem oil for the majority of the cleanings.

Thanks for the suggestion, Bushman.

[Bushman]

Dave, I have to admit that seeing that blue copper reacted color coming out on the patches was such an epiphany that I do clean with the copper solvent now. I'm thinking that I am still in the process of getting more out of my barrels as that patch always comes back with a little color on it, even when I think it is really clean. Years of Hoppe's No. 9 powder solvent cleaning I think left some copper behind.

[dave-t.]

I was impressed with the CR-10 stuff from barnes. I was not at all impressed with the Rem copper solvent. In fact, I can't say that I got any copper removed at all with it.

I followed the dirrections to the letter with the CR-10, and both barrels came back 'clean' in a lot shorter time than I expected. Patches went from dark blue-green to practically white after completing the first series. I did start in on a second round with the cr-10, but quit less than half way through it on both rifles, ran dry patches to get the solvent out and then finnished with a couple patches of Rem oil, a couple dry patchs, and a very light application of Rem oil (barely a spray on the patch) for the last trip through.

[ColoYooper]

When working on a new load I typically perform the following:

1) Select the bullet or bullets for the desired task. It appears you are hunting and I compare the Barnes TSX with the Nosler Accubonds (My results have caused me switched to the Accubonds)
2) Select a powder that will come closest to filling the cartridge at the max load. Pick a primer you can live with. Use that from now on.
3) Loadup 25 TSX cartridges in 5 groups of 5. Each group has 1/2 gr more powder upto the last group which is set at the maximum recommended charge. Seat each bullet just off the lands (assuming this will cycle in your hunting rifle)
4) Loadup 25 Nosler Accubond cartridges in 5 groups of 5. Each group has 1/2 gr more powder upto the last group which is set at the maximum recommended charge. Seat each bullet just off the lands (assuming this will cycle in your hunting rifle)
5) Fire (5)shot groups, through a chronograph cleaning once between the TSX and Noslers. Look for signs of overpressure, record velocity, Standard Deviation, and group size. One group should have a clear advantage with Velocity and Group Size.
6)You can quit here or...continue especially if the best velocity didn't produce the best group. Loadup another 50 with that above optimum recipe, and preferred bullet. Create 5 groups of 10 cartridges, each seated 0.005 deeper than the previous group, with the first group seated just off the lands. Fire a (5) shot group from each of the 5 seating groups, clean, and repeat. There should be 1 seating depth that will be the winner, and this should be obvious in both (5) shot groups.
NOTE1: The seating depth is from "just off the lands" to ~0.020 off the lands. We are NOT SEATING THE BULLET INTO THE LANDS.
NOTE2: If the first shot after cleaning is outside the group...discard it and judge the remaining 4 shots for that group.

[dave-t.]

Thanks ColoY.

I may try seating that ttsx deeper with the 48.5g load, because that is the estimated speed that I want to send those buggers out, 3050fps+/-.

Have you tried seating the barnes .050" off the lands? Supposedly there is some magic there, but I haven't stumbled into it yet.

[ColoYooper]

There really isn't any "magic" with seating depth. It works exactly like the B.O.S.S. system except you are tuning from the back end instead of the front end. Every rifle with a specific load has a sweet spot where the barrel harmonics produce the best group. Some speculate that the best spot is at the peak/trough where the oscillation velocity temporarily stops but the amplitude is the greatest. Others speculate that the best spot is at the node where the harmonic amplitude is zero, but the oscillation velocity is the greatest. Whichever reason, you will find (with a really good rifle) that as you step through the various seating depths, some depths will produce a larger symmetrical distribution, another depth will string primarily vertical, and another can string primarily horizontal, and finally the golden depth, will stack them all together. (which places me firmly in the node camp). I can usually find the "golden" depth within the 0.020 of the lands (more samples may be required). So while a seating depth of 0.050 may be great on Joe's rifle, there is no way to predict how my rifle will like it. However, the greater the distance that the bullet has to jump "free bore" to the lands, the greater the opportunity for it to engage the lands cock-eyed. And, unless you shoot moly coated bullets (I do) the bullet will remain cock-eyed until it is ~100yards down range and stablizes. This is never an enhancement to accuracy.

As for Nosler Accubond vs. Barnes TTSX, I found that I had better velocity AND groups with the Nosler, and there was less copper fouling. As for the elk I've dropped with the Accubond, they never knew what hit them with my 30-06.

[Sidekick]

I've gotten an improvement from deburring the flash holes and switching to benchrest primers. It just makes things a little more consistant.

[Bushman]

What about pushing in a couple of wind direction ribbon flags down range? That first group looks like it could have been influenced by some wind. I didn't realize how wind blew around bullets until I started shooting my Cooper .221 Fireball. That rifle is very accurate and I was having a good time making little bullet hole clusters down range until the wind came up. My 7mm-08 was not quite as susceptible, but still wind drift noticeable at 100 yards.

I assume that you are weighing each powder charge, case and bullet for consistency. They won't vary too much, but they will vary. That and you are shooting a big cartridge there with that .300 WM. When I shot magnum cartridges I would get a little punchy after a few rounds and while I might have been shooting the most accurate load of the lot, I couldn't tell it because of human error.

[dave-t.]

Bushman, I don't like shooting more than 10 in a row with the 300. When I started with that rifle for the day, I put a sandbag between the gun butt and my shoulder right off. Also, with the sandbags front and rear, and aiming at the bottom right corner of the square, I felt pretty darn solid with regard to consistant aiming point and good follow through.

There was some wind from 10-11 O'clock, but at 100yds, I consider anything under a gale to be a wash, especially with 30cal 180's at that speed. It may have been a factor with the 100grn ttsx load, but none of the other 257R loads showed any signs of wind affects, imo.

I was measuring every powder charge and seating depth, but didn't measure brass or bullet weights. I'd be happy as pie with any hunting load that is 1" group or smaller, but that stinging group has me thinking I'm just a hair off somewhere with the load from having a real eye popper.

Thanks guys.

[Bushman]

I sure don't see what I would call stringing from those three groups shown. Vertical stringing usually has to do with the bedding of the barrel or not letting it cool down enough between shots. I've got a solid bedded light weight barrel on my 7mm-08 and that one will string vertically if I don't let it cool. Not so with with either my 7 mag or the .221 as those both have free floated barrels. I don't like free floated barrels as much for hunting, but they do seem to be more forgiving at the range.

Also how about heat mirage? What you might be blaming on your rifle or loads could be what heat mirage is doing to the target image. I only shoot first thing in the morning as soon as I can get on the range.

[dave-t.]

That top group 1.05" horizontal, .3" or so vertical seemed like stringing to me.

The .6" triangle with the 117grn seems like a more consistant grouping, but I'm new at this.

Not giving much time between shots was something I ran into.

I fired my first two groups with the 257R as fast as I could load and get the sighht picture. The last two groups were the ones shown, and I fired the group, and then waited for the barrel tocool before shooting the next group.

I'm much more concious about that with the 300, as it seems to heat up faster, and stay hot longer.

My local range is only open 12noon-6pm. So whatever the wind, heat, rain, etc. is doing, I'm stuck with it if that is the day I plan to shoot. Even so, their covered benches still beats the pants off of a makeshift set up at home, but I have sighted in for deer season at home with sand bags off of the hood of the truck.