6.5 PRC Tuner Test

[Michael Lloyd]

I've been working on load development for a 6.5PRC I put together. It's based in an Aero Solus action and 1" diameter, full bull, 26" 1:7 twist Preferred Barrel Blanks barrel. BixNAndy trigger. MDT chassis. Nightforce scope. I've been shooting it suppressed but I don't like the groups I've been getting so I swapped the can to another rifle and installed a tuner brake. The first test was promising. I've shot it at 1,000 and it's not bad. I'm hoping the tuner will help me turn hits into groups.

On a hot day this load is a bit too hot for my comfort level so I'll back it down a tad.

Rifle

Target (100 yards). Further testing needed to be sure setting 8 repeats and is the best. 1/4" at 100 isn't terrible.

 

[Mschroeder40]

That looks like a pretty amazing development

 

[Michael Lloyd]

Considering it's an Aero Solus short action magnum action and a prefit barrel assembled to it by me, I think it's a good start.

I changed powder to N555 and I made a seating depth adjustment so I retested the tuner settings last weekend. I started at 0 again and ended up at 9.5 (1 mark counter clockwise).

Groups
Tuner 0: 0.217"
Tuner 2: 0.695" nope, wrong way
Tuner 9.5: 0.202"
Tuner 9.0: 0.337

I might be able to squeeze that down with further seating depth testing. Up until now this was the first time I've change seating depth since I found jam, etc. And, I should do seating depth before tuning,

Powder change was because N560 is hard on a barrel.

 

[Michael Lloyd]

Someone recommended that I get away from N560 and try N555 because N560 erodes the barrel. That was a good idea. I decided to see if magnum primers made a difference and tested that. They did. ES dropped to single digits and groups tightened up. I shot it at 300 yards yesterday. 100°F outside. The mirage was not so bad that I couldn't see the target but it was hard to see the hits. I put a barrel cooler in and walked down after every group was shot, a little over 3 miles worth so I got my cardio in

Results were favorable. I didn't shoot the other loads because there was no need to.

This is the 2nd target. 3 shot groups. The first target was used at 200 and 300 for sighting in. I had some rounds in the box that were close to the test rounds and I used those for sighters. The 2nd and 3rd group moved because I was trying to dial for center or at least closer to it. The wind laid down so group 4 shifted left. Group 2 changed so much, about 3x what it should have, because "my dumb scope" didn't remember that 1 click isn't 1/4" at 300. This is also where I learned that the best load you have can "spread out" if the shooter doesn't do his part. I saw the first 2 hits in group 2, got a little excited, and screwed up the last shot. Group 3 was also my error. The two best are .138 MOA and .140 MOA. I ran the barrel cooler between groups but at 100° air temp it didn't do a lot. All in all it was a good lesson in wind, the importance of concentration, and technique

 

[DeadEyeDeadly]

No Tuner, But an interesting avenue I'd like to explore.
Savage Target Action Rifle - 6.5 Creedmoor
28″ McGowen Barrel
Now has Sightron 8-32X56 Scope
Target - 5 shots, 300 yards. Fort Bliss Rod & Gun Club Range.

 

[Michael Lloyd]

I've been told that vertical stringing is powder or powder charge. That said, I saw first hand a couple of days ago, that stringing can be the shooter. In the past I blamed the can. Or it's all of the above. Still a nice 0.5 MOA group no matter what caused the stringing.

I started shooting my 6.5 with a can. I did a seating depth test in an attempt to get the groups to tighten up but wasn't happy with it. I posted in Erik Cortina's forum and he suggested changing from N560, because it's hard on barrels, to N555. For the record, N560 is definitely hard on barrels.

I changed powders and ES immediately dropped to single digits. I adjusted seating depth to .025" off of jam, it improved but I still wasn't happy so I ordered a tuner brake. I replaced the brake on my Sendero 7mm Rem Mag a few years ago with a tuner brake. It cut felt recoil and tightened groups a lot. I had one 3 shot group that was one hole at 100 yards but it didn't repeat. It consistently shoots 1/4" groups. Not bad for a 20 year old hunting rifle.

This photo is from Friday's 300 yard test. The precision shooting matte that you see looks like a towel because it is I have a matte ordered. The skis on the bipod and concrete bench top weren't getting along.

It's all the little things that add up to get a small group on target.