RMR 69 gr OTMs

[triggerjerk]

May have asked before.... can't remember, butt....

A friend who shoots Perry has a gizmo to sort bullets by bearing surface as it affects friction therefore pressure. Do any of y'all do this, and specifically, has anyone measured bearing surface on the RMRs? I have wieght sorted in the past, and the RMRs came out better than SMKs....

[markm]

I've never done that, but it makes sense. I wouldn't know how to accurately measure bearing surface.

[triggerjerk]

He recently gave me some of his old stuff, and I plan to measure such on RMR 69s ass soon ass I finish brass prep. No manufacturer labelling, but looks like what mounts on calipers to measure headspace/ogive seating depth with different caliber bushings. I assume the holes are at or barely under major bullet diameter, one for each end of bullet. I just figgered some of y'all may have already been there.... Guess I'll let y'all know what I come up with, unless I've already aggravated you too much with this bs.....

[Coal Dragger]

I've never done that, but it makes sense. I wouldn't know how to accurately measure bearing surface.

You can get close by measuring base to ogive.

A comparator kit for your calipers can accomplish this. I use a kit from Short Action Customs because I have a set of their reloading dies, but Hornady and other make comparator inserts that can measure base to ogive too.

[triggerjerk]

Hey, Coal Dragger. He gave me 3 caliper adapter/bushing holders and a menagerie of inserts. 2 red adapters and 1 green. Inserts are not interchangeable. Would you know whether the red would be Hornady and/or who manufacturers might be? Thx

[Coal Dragger]

Unfortunately I don’t know.

My SAC comparator kit for headspace and bullet seating measurements is what I’m most familiar with. All the SAC stuff has the dimensions of what it is engraved on the inserts.

[triggerjerk]

Gotcha. Thanks again

[grizzman]

I finally shot the 69 grain RMRs for groups. I used a LaRue 16” MGU. I probably won’t be using RMRs as my primary ammo for this rifle, but I thought it would be among my most likely platforms for good results.

I shot two groups with the suggested recipe from their forum. The first group was 1.2 MOA and the second was 0.8 MOA.

The other load was the same powder charge, but loaded to mag length in Federal commercial brass. The groups weren’t good enough to even measure.

If both of the LC loads were around 0.8 MOA, then I would have verified it with more groups and called it done if they performed as well., but they should do better. I don’t think I’ve ever not gotten at least 1 MOA from carefully made handloads, so I’ll keep trying. My avg velocity was 2695 fps with LC brass and 2650 with Federal with no pressure signs, so I’ll go up a bit and see what happens.

[MarshallDodge]

Hey, Coal Dragger. He gave me 3 caliper adapter/bushing holders and a menagerie of inserts. 2 red adapters and 1 green. Inserts are not interchangeable. Would you know whether the red would be Hornady and/or who manufacturers might be? Thx

I'm going to guess Sinclair, as green is the color of the caliper adapter/bushing holder that I have from them. Are the bushings made of steel? Mine are.

I have tried weight sorting and measuring ogive length, and saw a little bit of success in doing so. At the end of the day, I wasn't certain of the results, and if the results were worth the effort.

[308TRUMPFTW]

I finally shot the 69 grain RMRs for groups. I used a LaRue 16” MGU. I probably won’t be using RMRs as my primary ammo for this rifle, but I thought it would be among my most likely platforms for good results.

I shot two groups with the suggested recipe from their forum. The first group was 1.2 MOA and the second was 0.8 MOA.

The other load was the same powder charge, but loaded to mag length in Federal commercial brass. The groups weren’t good enough to even measure.

If both of the LC loads were around 0.8 MOA, then I would have verified it with more groups and called it done if they performed as well., but they should do better. I don’t think I’ve ever not gotten at least 1 MOA from carefully made handloads, so I’ll keep trying. My avg velocity was 2695 fps with LC brass and 2650 with Federal with no pressure signs, so I’ll go up a bit and see what happens.

What was your seating depth? I've shot a few at 2.245 with TAC powder and military brass they group fine but not spectacular. Good enough for steel targets and bowling pins.