New 6.5 Creedmoor Load Development

[kilotanker22]

Picked up a new Browning X-Bolt in 6.5 Creedmoor a few weeks ago. Load development went well. 140 ELD Match bullets, Lapua cases, CCI 450 primers and H-4350 powder.

I have been using the powder charge I settled on and adjusting seating depth to tune the load. Last range visit I had one depth that shot exceptionally well so I Loaded 50 more of them for further testing. I shot four groups of five shots tonight while recording velocities with my Lab Radar. All four groups look very similar in shape to this one. All four groups measured less than .35 MOA. This one just happens to be the best of the four. I am quite happy with this for a factory gun with no modifications other than lightening the trigger. Groups are measured from outside the bullet holes on the edge of the black carbon markings left by the bullet then bullet diameter subtracted from that measurement for my center to center group size.

Across all twenty shots velocity was very consistent.
AVG: 2778 fps
ES: 9 fps
SD: 3.7 fps

Today it was 32 F on the range. Last week when I originally tested this load it was 60 F. My average velocity today was only 8 fps slower than it was last week for the same number of shots. Like I said, very happy with this Browning rifle. I bought this rifle to hunt with, but maybe I will shoot a few PRS matches with it next year.

[kilotanker22]

I use Forster Benchrest FL sizer die that has had the interior surface polished. To seat bullets I am using a Forster Benchrest seater die.

[NHSHOOTER]

maybe a foolish question..100yds?

[Rimfire5]

Kilotanker

With thin paper targets like your shooting, I find that the actual bullet holes, even with the black powder ring, might actually be slightly smaller than the 0.264 that you are subtracting. The paper lets the bullet slide through and then shrinks back a bit.
The only bullets that I have measured that were right on caliber hole sizes are .22-250s that were shot close to 4,000 fps muzzle velocity.
I use 80 lb paper for my targets and the holes are still slightly smaller than caliber for my .223, 6.5mm CM and .308s.

You may actually have even smaller group sizes than you are calculating.
I use the On Target PC software ($12 and a great investment) and select a circle size that matched your bullet holes. It measure center to center.

[cdoc42]

Kilotanker and Rimfire5, I don't know if this is "cheating," but I've found the bullet holes easier to measure by laying the target face-down on a flat surface and gently pushing the frayed edges of the bullet holes back to their flat position. A wet finger helps. Then I cover that with a piece of "Scotch" tape. Turn the target over and the holes are obvious circles with a black powder ring. I measure the outside diameter of the group with a "Professional Combo Circle" template made by Staedtler purchased at Staples, then subtract the bullet diameter.

PS: Kilo- I traded a Kimber in 6.5 Creedmoor that I could not get to shoot less than a 1.5-inch group for a Browning X-Bolt that leaves me more than impressed. Both Hornady SP and Sierra HP in 140gr impact at the same spot and tie for groups under 1 inch. I used a 140gr Hornady ELD-X and killed a common paint spray can with a dead-center shot at 1000 yards.

[hounddawg]

fire four or five single shots not in a group. Measure the OD of each hole with your calipers then get an average. Then subtract the average from the edge to edge of your groups. If you use Ontarget you can also put that value into it for the caliber.

Great groups BTW. If it shoots like that consistently and you can center the groups you would be very competitive in International Benchrest for score. My 30 Major is normally a .3 or .2 rifle for 5 shot groups and I have shot several 20+X targets when the wind cooperates

[kilotanker22]

Originally Posted by Rimfire5

Kilotanker

With thin paper targets like your shooting, I find that the actual bullet holes, even with the black powder ring, might actually be slightly smaller than the 0.264 that you are subtracting. The paper lets the bullet slide through and then shrinks back a bit.
The only bullets that I have measured that were right on caliber hole sizes are .22-250s that were shot close to 4,000 fps muzzle velocity.
I use 80 lb paper for my targets and the holes are still slightly smaller than caliber for my .223, 6.5mm CM and .308s.

You may actually have even smaller group sizes than you are calculating.
I use the On Target PC software ($12 and a great investment) and select a circle size that matched your bullet holes. It measure center to center.

I have read about this. This is the reason that some cowboy action shooter use was cutter bullets. Was cutters leave perfect round holes in paper. It was snowing some so the targets were a little wet.

[kilotanker22]

Wadd cutter bullets.

[Bart B.]

Best way to get precise diameter of bullet holes in targets is measuring the barrel's groove diameter.

[kilotanker22]

Originally Posted by Bart B.

Best way to get precise diameter of bullet holes in targets is measuring the barrel's groove diameter.

Had not thought of that Bart. The pressure will cause obturation of the bullet to meet the groove diameter

[hounddawg]

Best way to get precise diameter of bullet holes in targets is measuring the barrel's groove diameter.

lol and here I thought the best way to get the size of a bullet hole in a target would be to measure the bullet hole

[kilotanker22]

Originally Posted by hounddawg

lol and here I thought the best way to get the size of a bullet hole in a target would be to measure the bullet hole

Bart's statement makes sense. The maximum size the bullet will be will be the same as the groove diameter. This Browning barrel is a 1:7", 3-groove barrel. The best measurement I could seem to get was .2642" for groove diameter.

[kilotanker22]

Originally Posted by NHSHOOTER

maybe a foolish question..100yds?

yes

[hounddawg]

and what is to say that the bullet hole will be the exact size of the barrel groove. I can shoot a round at target paper, one at printer paper, one at card board, and one at plastic and every one will have a different size due to each will tear a bit differently and none wil be the groove diameter of the barrel.

If you want to get a accurate group size shoot 5 shots not in a group and measure each one then average them and you will have as close as you can get to the hole size for that particular material on that day with that bullet

[kilotanker22]

Originally Posted by hounddawg

and what is to say that the bullet hole will be the exact size of the barrel groove. I can shoot a round at target paper, one at printer paper, one at card board, and one at plastic and every one will have a different size due to each will tear a bit differently and none wil be the groove diameter of the barrel.

If you want to get a accurate group size shoot 5 shots not in a group and measure each one then average them and you will have as close as you can get to the hole size for that particular material on that day with that bullet

Makes sense. I think Bart was referring to my using the standard bullet diameter to subtract from the size of the group. If the groove diameter of the rifle was different than that of the bullet before being fired, the diameter of the bullet would be different than the arbitrary number I used. However, my groove diameter is only .0002" different from the number I used so it would be a moot point for me.

I do understand your statement about the hole sizing. It just never occurred to me to use anything other than bullet diameter.

[hooligan1]

Kilotanker22, what is intended use of rifle and those loads?
Ive built some good plinking loads using Noslerblems, 140 grn rdfs to be exact with rl19, Starline lp brass and CCI 200 lrp.
It groups less than an inch at 100 and the best thing is those blems are cheap enough... When they have them that is...

[hounddawg]

Nothing wrong with Nosler blems, when you can get them. I have shot them in matches with my .269 Rem many times. I consider Nosler CC's the equivalent of SMK's

[ed308]

Agree with that. I’ve got thousands of Custom Comp bulk bullets in 5 or 6 calibers. Load similar to the SMK’s like you said.

[RC20]

Best way to get precise diameter of bullet holes in targets is measuring the barrel's groove diameter.

Now that has me shaking my head, we are getting down to .002 here?

If you are shooting a match the score keeper will tell you what it is!

Regardless, that is some fine ammo (those ES and SD are to die for but you should run 50 identical) equally some fine shooting and damned impressive for a factory gun.

My 6.5 Shilen barrel on a target receiver (left port only, solid) are not that good.

If I get the groups down under 1/4 MOA, I just guess and go home happy happy happy