So I am working on a load for my 7mm-08 pushing a Barnes 120gr TTSX with RL17. I start at 45.5gr and shoot a .635" group, I go to 46gr and the group opens up to 1.5", same with 46.5gr and 47gr.
I am used to seeing a group open and close up as powder is varied, but not to shoot a nice tight group and then go all to heck and stay there. Perhaps my gun just like 45.5, but can you really get that much variance with .5gr.
Think I am going to ask Santawife for a chrony for Christmas, I would really like to know what is happening velocity wise.
Any Comments?

I guess when it likes a load it likes a load.

My 270 I load 150 grain NP's for is weird. It likes The slower loadings best and the closer you get to the lands the worse the groups get.

I loaded some 150 grain barnes original x's and it prefered them long and the hotter I loaded it the better the groups got all the way to max, light loads were 3" or so best group I got as around .75 inch.

you may have an accuracy node up higher but I don't know what the data says...

yeah, a Chrono is a damned good idea for reloading
if you are getting near the upper end of loads knowing where you are at with your gun for FPS is very crucial

I've had a chrono for decades. Can't really imagine hand loading without it. You cannot truly know what's going on without knowing actual MV.

I always read/heard after getting close, back down to 2/10's or 3/10's increments on smaller cases, short action.

.5 grain increments is too big of a jump for load testing in a 308 sized case. You can easily pass a sweet spot between the .5 jumps and not know it. But yes, .5 grains is enough to totally change up the accuracy of the load. In my comp gun, I can see a difference in .2 grain charge difference. Normally your next sweet spot will be about .7 to 1 grain higher. There is almost always a low end and high end sweet spot. I try to load on the high end sweet spot, which is just before or at max pressure.

R17 is a great powder that yields fast speeds. But, it is very temp sensitive. So, a winter max load will be over max and a hot load during the summer time. Also, the accuracy can change with the temps. So, I try to stay away from this powder.

Thanks Chad and I appreciate the info on RL17. I guess I will need to try some other powders with it. Good thing I just ran out of the stuff, if you say it is that temp senstive I won't buy more. Now I have to shoot up all my 6mm and .243 rounds loaded with it.

I guess I need to break out the Varget again or try some RL15.

Chuck, have you considered H4350?

You're welcome! With the 3 calibers you mentioned, I would put H4350 at the top of my list, especially for the 7mm-08 and 243. I have done LOTS of testing with powders, and H4350 seems like it was made for the necked down 308 cases (243, 260, 7-08). I can not find anything more consistant that shoots as good as it does.

Chad,
have you tried H4350 in the 280 Ackley and 140g bullets?

No, but it would be a good choice. H4350, H4831 or R22 would be good one's with that weight bullet. If you can seat the bullet out further than normal length, a slower powder like 4831 would be good.

I have some H4350 laying around, will give it a shot. Unfortuantely also being a bowhunter, my load testing days are over until January. I got to dance with what I have.

Chad, Have you ever done a bulk buy on the H4350 powder? If not whats the bet place to get that in 8# or higher volumes?

Barnes Manual No 4 shows accuracy load RL 15 41.0 grains up to
44.0 grains w/a speed of 3081, 94% load density..They do not list
RL 17 as a preferred load..Varget is 42.0 to 44.0 gr and 3025 fps
same denisty..I'd try to use the manual they produce rather than
a load you may have had work on conventional projectiles ..and
remember to throughly clean your weapon each time..no blue on the
patches when done..Ty Herring is the lead tech at Barnes and he's
always been very helpful to me..You can spend $200+ working up a
load if not careful..Don

I have talked to Ty several times and I own all the major books. I just went off the map with the RL17 because of the experiences other have had with it. I am impressed with the low end results, but upon hearing Chad's take on it. I am going to try the H3450. I have used Varget and RL 15 with the 7_08 and the results were okay 3/4" groups. I want to find the groups I got with the RL 17 with something less temperature sensative.

In addition to the 4350 powders, Varget, and Re-15, IMR4320 will give top velocity and good accuracy with the 120 gr pills. But when you move up to heavier bullets, 4320 burns a little too fast IME. I load for 2 different guns in 7mm-08, and if I could choose only one powder for fine accuracy and high velocity, it would be Re-15.

tried crony a few times give up on it and i loads several rounds not saying it not the way to go but ma 300 yrd target tells me a lot more

Yes. I normally don't sell components, but since you are in Plano, I can get some powder in for you. Send me a PM or give me a call to discuss.

All the powders you guys are talking about are really good powders and should work very well. Each one has their pluses and minuses. Since I have played mainly with H4350, it's what I go to. I try to stick to the temp stable powders. But when I find loads that are just "hammers" (extremely accurate) and the ammo will be used for 300 yards or less, I'll load that powder. So, R17 would be fine if it's not a long range load. I still load R15 and IMR4350 for a lot of my personal hunting ammo, and they are not very temp stable. But they shoot great!

Chuck, I loaded some 150 TTSX for my 308 w/Varget..at max they shot about a perfect circle at 100 yds, 2 in across..I dropped 1/2 grain and the 5 shot group w/3/8ths in side to side..all one
hole..I had several more loads wored and tried them all from a fat 1 ins to about 1/2in but the 1/2 grain off max w/the Varget was by far the better load. When working up loads on Barnes Products, I've found sometimes it's expensive..I do clean my weapons throughly every time because of the particular nature of
the solid copper projectiles..However, about every third time I
end doinq quite a bit of work..Try Ty Herring at Barnes..he's a good guy and very helpful..Don Dial, Pipe Creek, TX

Gotta love the Hodgdon Extreme powders. Chad knows his reloading, I would listen to him.

Chuck, I recently reloaded some Barnes W Varget in my 308..max load I got about 1 1/2 in circle..reduce .05 grain..all one hole
about 3/8in 5 shot group..I really like Varget in the reloads on
the 308..this caliber is not really particular but I load a Remington & a Sako w/different twist...and both rifles shoot one
hole groups with the powder..but usually not quite the max load.
Don