Nosler 6.5mm 130 gr RDFs

[Sticks]

AustinTom - Load 10. Fire 5 normally, then single feed 5 and let us know how they do.

I had a long talk with a gunsmith at the last Sporting Rifle Match and he is convinced there is a concentricity issue caused by the barrel extension. The feed ramps and lower lugs cause the round to nose up into the top of the chamber before diving into the throat.

[centerfire]

AustinTom - Load 10. Fire 5 normally, then single feed 5 and let us know how they do.

I had a long talk with a gunsmith at the last Sporting Rifle Match and he is convinced there is a concentricity issue caused by the barrel extension. The feed ramps and lower lugs cause the round to nose up into the top of the chamber before diving into the throat.

A concentricity gage would easily identify if the action was bending the loaded cartridge when feeding.

[AustinTom]

Alright sticks. Check out the top two groups on this target. Mag fed was the smaller group. I think it's just my shooting. I don't think I'm getting any concentriciy issues from the action working.

Centerfire, I don't own one, and probably won't be purchasing one anytime soon.

I've pretty much settled on 26.9 gr AR Comp, BR4 primers, and 2.285 COAL. I've made up a bunch of these and tomorrow will be testing the BC of the bullets. Will be shooting out to 1000 yards.

I chronographed 10 rounds of this loading ( the center group on the target) and got these results

Ave 2429
Hi 2435
Lo 2424
SD 3
ES 11

IMG_0955.jpgIMG_0954.jpg

[Crusty]

I'm going to load up some 26.9ers too. From what I found previously with 123s, the same node should be found with 130s around there, though I didn't find one with my initial OCW spread but I now know that I had neck tension irregularity issues going on which likely distorted those groups. I need to get back into the 2400's MV for the 1000y range and that increase could do it.

I've been able to tighten my groups (ESs and SDs are better too) by applying more care to ensure that the bullets engage the rifling consistently. I've turned my necks (.010" walls on Hornady brass), IDs sized to .005" under bullet diameter and then die expanded back to .003" under, wet pin tumbled to remove the neck soot, and the hBN coating is doing well to eliminate non-shooter fliers. My latest batch has also been bump sized rather than FL sized for a closer fit in the chamber so that the bullets all start from nearly the same location in the barrel.

I guess I'm gradually working my way towards match grade ammo because that's the level of performance I'm looking for, but at the very least it keeps me out of beer joints. ☺

[AustinTom]

Very cool Crusty. Glad that's working out for you.

[Sticks]

Alright sticks. Check out the top two groups on this target. Mag fed was the smaller group. I think it's just my shooting. I don't think I'm getting any concentriciy issues from the action working.

...

Did you make a POA shift or scope adjustment between mag fed and single feed? 1" change at 100?

[AustinTom]

Did you make a POA shift or scope adjustment between mag fed and single feed? 1" change at 100?

Scope adjustment. Dialed down .6 mil to account for the magnetospeed for the first (center) group. Then shot the mag fed group but forgot to dial back up.

[Sticks]

OK.

Good groups, I like the horizontal string, IIRC that is shooter error, not fluctuations in ammo, at least I hope so. Speed is in the borderline range to make it worth the effort over the 123s.

I am a little concerned that I am running a lot more powder, but then I am loading longer and primarily bolt gun with these. I have not tried in my ARs yet.

Weather and work is going to screw me out of testing again. Rain and getting shipped out of state next week means I need to sped time with the GF.

[AustinTom]

OK.

Good groups, I like the horizontal string, IIRC that is shooter error, not fluctuations in ammo, at least I hope so. Speed is in the borderline range to make it worth the effort over the 123s.

I am a little concerned that I am running a lot more powder, but then I am loading longer and primarily bolt gun with these. I have not tried in my ARs yet.

Weather and work is going to screw me out of testing again. Rain and getting shipped out of state next week means I need to sped time with the GF.

Well the extra velocity could only be beneficial at longer distance.

I got out to the big range today. Stretched the legs out to 1000 yards. I got two different results using two different ballistic calculators. I used the free online Applied ballistics and the free hornady app. Hornady app called for 11.4 mils elevation at 1000 and the AB 11.8, using the .307 G7 number on the box.

The hornady iPhone app was spot on. I shot steel from 300-1000 and had no trouble making hits at all distances. Winds were gusting up to 18 mph, and I struggled with that for a good bit of the day.

[Crusty]

I've got an old Android phone so many of today's phone ballistics apps won't install, but I found an older one named Strelock that was cheap (IIRC <$5) and it generates all the shooting data I'll ever need right in my pocket. If you've got a newer phone, most everyone recommends the Shooter app. for the same purpose.

I did some volume measurements this morning and I determined that with 130 RDFs seated at .130" off the lands (in my rifle anyway) a charge of 26.9gr of AR-Comp has a charge density of around 95% in a Hornady case sized to spec. FWIW, my measurements of AR-Comp determined it to have a density of .94 of water. So you can seat a bullet in an empty unprimed case to your bullet depth, weigh it, fill it with water with a syringe thru the flash hole and weigh it again and determine your case capacity of water in gr, then convert that to gr of Ar-Comp using the figure above and finally determine the charge density in your load at that bullet depth. For example, if your case holds 28gr of water, that's equivalent to (28/.94 =) 29.8gr of AR-Comp, so a 26.9gr charge would have a charge density of ~90%.

[Crusty]

Shot some groups today seated at different bullet depths and got a group at .140" off the lands that was better than the groups at the .130" off depth that I've been using. I ran a spread all the way from .120" to .150" off in .005" increments and the .140" produced the tightest group of the day. I can't upload a group pic today for some unknown reason.

Also, I annealed my cases before loading this batch and I got back the ~100fps MV I lost somewhere along the way as my brass aged. I'm convinced that neck tension has a significant effect on MV and consistent neck tension has a big effect on groups.

[BluntForceTrauma]

I'm convinced that neck tension has a significant effect on MV and consistent neck tension has a big effect on groups.

Guy who taught me reloading (who has since moved from Minnesota to Wyoming) had a bolt-action rifle in .308 that would not shoot.

But damned if he wasn't gonna fix it and MAKE it shoot.

Says he dumped almost $3,000 in gunsmithing on it and thing STILL wouldn't shoot.

Had an idea and as a last resort he bought a $17 Lee Factory Crimper.

Thing shot 0.25 MOA.

He wept.

[AustinTom]

Shot some groups today seated at different bullet depths and got a group at .140" off the lands that was better than the groups at the .130" off depth that I've been using. I ran a spread all the way from .120" to .150" off in .005" increments and the .140" produced the tightest group of the day. I can't upload a group pic today for some unknown reason.

Also, I annealed my cases before loading this batch and I got back the ~100fps MV I lost somewhere along the way as my brass aged. I'm convinced that neck tension has a significant effect on MV and consistent neck tension has a big effect on groups.

Interesting that you saw such an increase in velocity.

What sort of SD and ES were you getting?

What barrel are you running?

[AustinTom]

Guy who taught me reloading (who has since moved from Minnesota to Wyoming) had a bolt-action rifle in .308 that would not shoot.

But damned if he wasn't gonna fix it and MAKE it shoot.

Says he dumped almost $3,000 in gunsmithing on it and thing STILL wouldn't shoot.

Had an idea and as a last resort he bought a $17 Lee Factory Crimper.

Thing shot 0.25 MOA.

He wept.

I may have to buy one of those.

[Crusty]

My SD and ES weren't as good as I was seeing before (before: S 6, E 14, today: S 20, E 41) but I'm convinced that I can improve those with more careful neck prep. I want that extra 100fps for the long target so I'm willing to put in more work to make it perform better.

Something that surprised me was the group following the .140" group, only .003" longer, grouped terrible.

This batch of brass is getting pretty old (15x) and I'm thinking about switching soon to some new brass for further refinement. I'm also going to be annealing a lot more frequently.