Not having success with 260 Rem

[Larry Gibson]

"I think the twist rate is the killer."

That would be correct. The "odd flyers" are the result of the bullet exceeding it's RPM Threshold. The first load at 1515 fps is running 136,350 rpm....The heavier loads are obviously pushing the RPM over 140,000......

[Rcmaveric]

The 17.6g of Reloader seven was 1690 Avg FPS. I figured it was close to being over rpmd.

There are a few variables I need to illuminate though. Like sorted brass and double check neck tension. Try and rule out some posibilities.

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[RedlegEd]

Hi all. Went to the range today to check out some cast M1 and 260 REM loads. I'll just post the best two of the 260 REM targets using AA5744. There's really no "official" published data on light/reduced loads for this powder and cast bullets, so I interpolated from existing data starting low, and working my way up. Notice the difference from the expected velocity vs the actual. Another reason to never start high. Here are the results.

Basic Data:
Rifle: Remington 722, .260 REM, 24" Bbl (make unknown), 1:8" Twist (recently rebored from .22-250)
Bullet: NOE 266 FNGC, #2 Lyman (mine averaged 141.2gr w/GC & lube), sized 0.266, BAC followed by TL
Powder: AA5744, no Filler, each load weighed
Primer: WLRP
Brass: RP/Starline (stupid me...I mixed them)
OAL: 2.340 (Comparator), jump 0.03"

Overall observations: These had a little more "oomph" than the Blue Dot loads, but still easy shooting. Also, the barrel did not tend to heat as quickly (based on measured barrel temp.) I had no pressure signs at the upper limit, but had a few unexplained flyers, so I think I might have exceeded the RMP threshold of the bullet (thanks Larry Gibson.) I also posted a table of all the loads fired so you can see how the AA5744 did in my rifle with these bullets (and mixed brass ...[sigh.]) I believe the best load will be between 13.0 and 13.5gr. If you notice the group locations relative to the aim point, they're right on top of each other.


Attachment 229311

Attachment 229308 Attachment 229309

Ed

[Rcmaveric]

Seams the going consensus is going to be sub 1600 fps. Around 1500 fps puts the bullet in the 800ft lb energy category though which is minimum hunting energy. So its an accurate and useable load.

External balastic calculator has me usable balastics out to 125 yards. Starts droping like a rock after that.

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[blue32]

I figured out the RCBS 6.5-140 SILH today at 50 yards.

PC with Eastwood light violet, sized to .265" with a gas check and seated over 17.0 gr 5744 at a COAL of 2.638". I also tried the same load with no check and the results were clear. Checked on the left. Unchecked on the right.
First six shots hit low (scope set for jacketed). After adjustment, another three shots. Adjusted windage. Final three shots in center.
The large orange circle on the right was shot with three rounds. One hit to the right of the top small target. The rest, who knows. Didn't expect the gas check to make such a big difference. I'll try with traditional lube next time but at least I have a baseline now. This has been quite the journey and reading a lot of old posts on here really helped, so a big thank you to everyone!

[blue32]

I wanted to revisit this thread because I'm still learning. While the bullet is the same the lube has been replaced with WLL carnauba red. COAL is the same but cases on the loads below have been FL sized. Alloy is 1:3 Lino to range scrap (maybe 12.4 bhn). Aside from the A5744 loads, these are unpublished loads.

This site isn't letting me upload any images but doesn't give a reason other than "failure." The following 4 shot groups are at 50 yards:
11.0 gr Unique, 2" and shooting 1" low. Previously had success with load and used as benchmark. Shot a second group to confirm lackluster grouping.
13.0 gr 2400, 1.75". Round point of aim group but not quite there.
14.0 gr 2400, 0.8". What an improvement one grain makes, and I have a lot of 2400.
17.0 gr A5744, 1.5". Promising round group.
19.0 gr A5744, 1.75". Would have been .75" without flier. Wish the powder wansn't so expensive.
17.0 gr H4198, 2.25". Vertical stringing. Might try the IMR variety if I can get some.

I finished the day blasting an 8" steel plate at 100 yards and landed every round (I'd rather do that than group shooting any day). It's so nice to shoot a modern scoped rifle in a modern cartridge for such a marginal cost. I'm going to enjoy watching my boxes of 6.5 jacketed bullets collect dust.

[blue32]

I was able to get the 14.0 gr 2400 load over the chrono: 1,607 fps average. SD was 17 so this will be my standard load.

[gwpercle]

Try a lighter boolit .
I was all set to jump on the 260 Remington band wagon . I wanted to load long heavy for caliber boolits like I do in my 7 X 57 mauser (160 and 175 gr boolits in it ) I had 500 308 cases to neck down to 260 Rem. and planned to use 140 gr. cast boolits ... but after reading the dismal results with heavy boolits and seeing some compaints on the rate of twist and short throat ... it's a shame what could have been wasn't ... those long sleek 6.5 boolits would have been good hog and deer getters !
I gave up on that idea ... still have 500 308 cases !
Gary

[blue32]

Try a lighter boolit .
I was all set to jump on the 260 Remington band wagon . I wanted to load long heavy for caliber boolits like I do in my 7 X 57 mauser (160 and 175 gr boolits in it ) I had 500 308 cases to neck down to 260 Rem. and planned to use 140 gr. cast boolits ... but after reading the dismal results with heavy boolits and seeing some compaints on the rate of twist and short throat ... it's a shame what could have been wasn't ... those long sleek 6.5 boolits would have been good hog and deer getters !
I gave up on that idea ... still have 500 308 cases !
Gary

I got it working now. Refer to post 26-27.

[blue32]

Not much of a group shooter but the load seems to be fairly consistent.

[Shopdog]

A month,maybe two ago?

Snagged a Timney Hit trigger,which I adj to 1lb. And a new to me,mint Bushnell elite 6500,4.5-30X50 scope. 28" Brux HV brrl about 1/2 used up by a F class shooter who gave me a VG deal on. Single shot R700 ADL. Shoots the Lyman 268666(think that's it) into low node bragging groups with IMR4198..something around 20g. Shoots the Saeco 140g into screamer groups,that would be called a liar if I posted the 5 shot sizes..... with juuust under, starting JB book loads of IMR4831. It is slap embarrassingly accurate. And I'm NOT fully ringing it out. In the pic below you can see my "light" (pure laziness) bag setup. Bought this Protektor aluminum,and non leather set because I don't mind leaving it out on the back porch whilst raining. And it's lite.

There's WAY too much bag movement working the bolt. I'm not a BR shooter,losing patience. Instead, step out.... send 3,5,or 10 downrange and go back inside. No sighters or foulers.

I also would rate my wind reading at about maybe a 3?... on a 10 scale. So,there is no doubt that a real BR shooter could easily set some records with this rig. It needs a little added weight in the HS stocks butt. The gun rides in the bag nose heavy.