Input on 300 yard groups

[BLC3128]

I've recently worked up a load for my 300 Weatherby and need some input on the recent data I have recorded.. I am not expecting benchrest results, but I am always looking to improve my results. So any input is highly appreciated. This rifle is a long range hunting rifle and I like to shoot steel plates out to 1,300-1,400 yards. To provide as much detail as possible-

The gun is a Terramark, that has been fully epoxy bedded ( action, recoil lug, +2" of the barrel) . I torqued the action screws down to factory specs (55in/lbs), Trigger pull is a nice 2.5lbs (its a hunting gun). I have a Ken Farrel 20 MOA base that's bedded, with night force steel rings. Everything seems tight in those regards, but I do have the factory Weatherby freebore.

The brass is 3x fired norma brass. I deprime, tumble, uniform & clean primer pockets, neck size -0.002" (bushing die), body size and bump the shoulder back 0.002", I weigh my brass and all of my brass weight is within 1/2%. I do weigh my bullets and I have a bunch of 215.2gr bullets. When I seat my bullets I use Redding dry lube to lubricate the inside of the neck. I do use a Hornady concentricity tool to make the loaded ammo as concentric as possible. Note* I allow the brass to reach 2.820" before I trim. All of my dies are Redding dies.

I recently worked up a load and settled on a terrific combo. I kept my seating depth at max length 3.724" (I seat bullets off the ogive. The node is around 1.25 gr wide and I settled on 88.4gr of N570 pushing a Berger 215 @ 3026. I use Federal 215 primers. With this combination My ES is 11 and SD is 4.5. I shot a .349" 3-shot group @ 100 yards with this.

My shooting setup is a Bald Eagle adjustable front rest with a heavy front bag and a heavy "rabbit ear" rear bag. I use the free recoil method while shooting.

Over the weekend I began to test seating depths. With that being said I shot 5 shot groups of various seating depths at 300 yards. My best seating depths are as follows.

I let the barrel cool ~3 minutes between shots and use a chamber cooler.
I let the barrel cool ~15 minutes between groups and use a chamber cooler.

Base to Ogive - 2.915"
88.4 gr N570
AVG Velocity 3021
ES 11
SD 4.5
Shot 1 - Low , slight right
Shot 2 - Lower right of inner ring
Shot 3 - Lower left of inner ring
Shot 4 - Left of center
Shot 5 - High, slight right of center
Group - 2.615" (I did not count the cold bore shot. It was a carbon free barrel. I do not remove copper until accuracy falls off).

Base to Ogive - 2.870"
88.4 gr N570
AVG Velocity 3017
ES 22
SD 8.2
Shot 1 - Right high
Shot 2 - Middle high
Shot 3 - Right high
Shot 4 - Middle high
Shot 5 - Flyer
Group - 1.913" (I did not count the flyer. It was my fault I rushed the shot and moved the rear bag).
*Note, prior to this group I did adjust my elevation by 0.5moa up and 0.25 moa left*

I really like how group #2 shot, but I cannot explain the spacing between them. Would increasing or decreasing neck tension improve my groups?

 

[WeiserBucks]

Get the barrel properly conditioned and don't dial the scope. You're introducing multiple variables.

 

[Quicksilver338]

I would tune your seating depths in smaller increments. Seems like most bullets have a .010" window where they'll cooperate then I've seen some blow apart just that quickly outside the window.

 

[BLC3128]

I was thinking about shooting 2 ten shot groups at 600 yards. Each on a clean barrel.

 

[Quicksilver338]

3-5shots should be plenty, given the shooter is consistent in those groups. SD/ES is a great indicator of what's going on too.

 

[kiwikid]

Can I suggest that try either a 3 or 5 shot group with ammo that has not been straightened in the Hornady tool. I may well be wrong but I can't see how straightening a round by holding the bullet tip at one end and the base of the case at the other and pushing on the neck doesn't in some way distort the brass in the neck.

 

[Remmy700]

Where are the groups!!! Dang they that bad u just deleted them like that! If so start over brother

 

[WeiserBucks]

I was thinking about shooting 2 ten shot groups at 600 yards. Each on a clean barrel.

A clean barrel is your enemy, put 50 rounds down it and then get serious about testing.

 

[BLC3128]

Where are the groups!!! Dang they that bad u just deleted them like that! If so start over brother

The pictures are in the OP.

 

[L.Sherm]

A clean barrel is your enemy, put 50 rounds down it and then get serious about testing.

50 rounds is alot for a factory tube.
Dont do load development on a clean barrel though.

 

[L.Sherm]

I'm not so sure of the 2" of the barrel being bedded. You could be inducing some stress as the barrel warms.

 

[Kansaswoodguy]

Stop with the barrel cleaning its counter productive.

 

[Sam Pace]

You're under MOA @ 300 yards with a cannon. You're not trying to achieve bench rest results. Honestly, what more would you prefer to see? I'm not trying to be negative here. I'm paying you a compliment. I think you might have achieved the performance level your rig can achieve. Just my opinion.

 

[Ronald W Schaefer]

Your techniques and process seem solid. FYI, I have a great load for my .300 WM: 180 gr Barnes TTSX, 79 gr IMR 4831, Fed 215 primer, Weatherby Brass, Max COAL. 3208 fps with a 26" BBL. I been there and back again and always return to that load. How did you break in your barrel? I started using the break-in regimen from Fierce Rifles and had good luck with it. Fierce firearms guys recommend:
Your break in will require shooting one box (20 rounds) of ammo

1. Shoot one round and then clean
   Do this for the first five rounds.
2. Shoot five rounds and then clean
   Do this for the next fifteen rounds.
3. Shoot a fouler round and then a three shot group for accuracy.

NOTE: Allow barrel to cool before shooting each series of break-in rounds to avoid unnecessary throat erosion. Do not shoot your rifle in succession until the barrel is too hot to touch with a bare hand. This can burn the throat out of your match grade chamber.

When cleaning we recommend the following items

• Use a quality one-piece cleaning rod.
• Use high quality patches.
• Use a bore guide.

Clean from chamber end only.

Clean powder residue from bore using a high quality barrel cleaning solvent.

Follow with a copper remover like Barnes CR-10 Copper to remove copper fouling. Follow the instructions on the bottle.

Finish with a patch lightly coated with gun oil. Your rifle is ready to shoot.
Remember to clean your rifle after 20-30 rounds.

This process can be done even though you have already been shooting the rifle. I did this with all three Fierce rifles we've had and two Weatherby factory rifles, it helped.