Home Forums Reloading Big Game Rifles Tweaking bandloads

I'm working with 3 rifles at the moment. 2 have been easy and used long established loads ( 308-varget-165s; 270-h4831-150s). My 06 is in need of some load tweaks. I'm trying to decide the order to start without shooting a 100 bullets.

Tweaks I've used in the past include (and in order of usage)

Vary bullet seating depth
Use different primer
Use different bullet
Use different powder

The last 2 are more drastic than the first 2.

My gun shot 1.4" to 2" groups (gross measurement). They aren't horrible but do measure more than I was hoping to get to a starting point. I'm looking at picking the 2 best groups (180 PT-58.0 H4350 and 180 AB-59.0 Hunter) and playing with the seating depth to see if groups shrink. My goal is a repeatable 1" net group size (1.31 gross).

Before I start cranking out a bunch more handloads with tweaks, wbat have you guys found to be the most influential tweaks to consider and/or start with?

FYI - gun has been bedded, trigger tweaked, barrel free floated, may box 'free floated', etc.

Run out of loaded ammo is ahead of all that other stuff.

For standard cup are core bullets in a hunting rifle, start at magazine length with the minimum starting load. Work up with the powder charge, then, if necessary, in with your OAL.

With an old style stick powder use a cold primer, think CCI200, Ball powders need a hotter primer such as a WLRM.

I omitted that tidbit - all shells have been straightened to less than 0.002" run-out.

I'd also include as a number 3 in order is to tweak powder charge by 0.5 grain up/down of most accurate initial loads.

59.0 gr Hunter, 180 Partition, WLRM, Rem brass, 3.333"










P

What are the runout numbers before they get straightened?

I've found cartridges that require much straightening don't shoot as well as cartridges that were assembled naturally very straight.

Initial case neck runout varies between 0.002 and ~ 0.007. I also cleaned up the necks in an attempt to ensure more uniform neck wall thickness.

In my limited observations, mainly because I just started correcting bullet runout, I haven't seen much difference between starting with the straightest cases and not segregating cases based on initial neck runout. Maybe I'll try that.

I gotta say my Kimber 308 has me raising expectations. I don't have 50 shots through it yet and it is shooting sub-MOA. The second 3 shot group, ~ 8-9 shot through the gun, produced a sub-MOA group. I did have a shortcut and used a known load (Varget, 165 Horn, fed 210) but it is one of the most accurate rifles currently in my safe. The worst group it has shot so far has been with 150 NPT and IMR 4166 and measures ~ 1.5" gross. I'd bet if I put more magnification on it I could shoot 3 shot ragged holes. It likes to shoot 2 shots cutting and a third just barely out. I think thats all the better I can shoot/hold using a Kimber. My Kimber 270 is alot like the 308 but likes to shoot MOA cloverleafs using H1000 or H4831. The 06 will come around but will take a bit more 'work' - its more normal for me than either of my other Kimbers. Kimbers really suck and are tough to shoot

P - I'll try that exact load. I've tried Hunter in ~ 5-6 30-06 and it hasn't been stellar in any of them. I know JB prefers Hunter but in my experience its hasn't produced. This latest rifle is about normal for me with Hunter. My ES was very, very low with it this go round and the groups weren't horrid. I've had it shoot 3"+ groups before.

I also notice you are using a WLRM primer and Rem brass. I have both and will likely try that as well. I have 300+ WW brass and always default to it but a handful using Rem brass wouldn't hurt.

Thanks.

OK.

This is exactly how I prefer to do it.

Get the powder charge optimized, then play with seating depth. Start with the bullet as close to the lands as you can get it. Just shy of the lands if you are able or as far as the magazine will let you otherwise. That only leaves you one way to go.

Exactly! Then if you shorten OAL, pressure only comes down. If that doesn't get the accuracy you want it's back to the beginning with a different component. Powder first for me.

And that is a nice side benefit.

The number of bertz generated by the handwidth could also be a factor.

Even moreso with a suppressed carrier...

I always start with the bullet I want to shoot, and stick with it until I can either get it to shoot or give up on it. Less variables to deal with that way, and I can almost always get a given bullet to shoot by varying the powder and seating depth.

Once I decide on a bullet I pick the most promising three powders based on velocity from the reloading manual and load up five rounds in each of three different charge weights ( 1 or 1 1/2 grain increments) at the top end of the range. No sense fiddling around finding an accurate load in the low end of the range when you can just as easily find one in the high end. I should add that I use a chronograph to make sure I'm in safe territory so that pretty much does away with the need to start at the low end of the range and work up.

So that will load out 45 and I will round out the box of fifty so that I can keep the box with all the brass having the same # of firings.

I just load all the rounds either at the magazine length or 10 thousandths off the lands if I have room.

I can almost always find at least one or two good-shooting loads with the one box of loaded ammo. And then tweak the seating depth later if needed.

This is what I tend to do as well. I want velocities near the top - doesn't seem to make much sense to me to run a larger chambering to the next lower tier might as well start with the smaller case. Case in point - my step brother has a nice M700 Ti in 30-06. It groups 180 Partitions into nice little groups - at 2650. Run them faster and groups open up to 1.5-2.0 incbes. My 308 runs a 180 at 2650 and shoots small groups without the recoil. BTW he won't let me fix his rifle. It needs bedded badly......

I'll likely try the two appropriate new Enduron powders and work with the best 2 on seating depth and likely try Fed 210 when I get to that point.

Yep, instead of worrying about the little things, fix the big ones first. Get the runout handled, set up the die while you are at it to bump the shoulder no more than .002, then bullets/powder. The rest are tweaks, and tweaks won't make a 2 in. gun a 1 in. gun.

Looking for that big a change you'd need to switch powders in my experience. Smaller "tweaks" I try to do with OAL but unless you're married to that particular powder I'd try a different one. When I work up a new load I try to start with a couple different powders and work a 3-shot/group ladder starting low to high, pick the best and refine from there. Rarely have I needed more than 35-40 rounds to find a good shooting combo.
I don't get the chrony out until I've settled on a load to determine the velocity to calculate drop from there. Critters don't know the difference between 2950 and 2650fps and I don't want to be influenced by the numbers unless I'm getting close to max range

Point made and taken.

Except a significant difference exists on drop and wind drift between 2650 and 2950. If you optimize trajectory and using normal BC, drop changes by 10-12 inches, wind drift by 3;4 at 500 yards. If you plan to shoot no more than 300 yards, I'm with you. I'm setting things up to maximize my chances out to 500. In my view that requires 1 MOA, a decent bullet, and use all the velocity a cartridge can generate. I won't quibble over the last 50-75ft/sec but don't see the need to leave much velocity on the table.

First, you made the assumption that he hasn't handled runout from the get-go, which does not seem to be the case. No pun intended.

Second, changing powder and charge weight is more than a tweak. It can make a much bigger difference than taking a 2" group to 1".

Third, using an FL die to minimally size your cases is not the only way to skin that cat.