Load question

[jsthntn247]

Remington action loading a 6.5x47 with 130 Norma's. I started at 35.5 and went up to 37.4 gr of Varget. Got decent groups and a node at 36 and 36.3 with groups around 1/4" and 2820 fps. 36.6 opened up to about 3/4" 36.9 opened up to 1.5" 37.1 went about 2.5" and I don't even know where some of the bullets at 37.4 went. Any clue what's going on? Usually groups will open up on a scatter node then come back together for the next node not just keep getting bigger.

 

[Shaggy357]

Maybe the second node is lower than the first. Wouldn't be the first time someone got the high node in the low end of the testing. If my 260 did 1/4" groups at 2820 I would be tickled pink....

Steve

 

[jsthntn247]

I'm fine with the speed and accuracy at 36. I've just never seen one go completely haywire before pressure signs develop.

 

[FeMan]

I don't have quick load, but I suspect that 37.4 of Varget is over max. Maybe not but with my experience with the 6.5x47, it hides pressure signs like a magician. In any event, I would shoot what it likes. If you don't like your results, I'll trade you

 

[jsthntn247]

Looks like everybody and their mother shoots 37-37.5 with a 130 up over 2900 with a 26" and longer barrel. I was wondering if a non bushed bolt face could be causing the issue once pressure builds up.

 

[4xforfun]

I can't imagin a gun capable of 1/4 inch groups shooting the same bullet with a different charge at over 2.5". Did you go back and conferm the 1/4 load again (and again)?

 

[jsthntn247]

I can't imagin a gun capable of 1/4 inch groups shooting the same bullet with a different charge at over 2.5". Did you go back and conferm the 1/4 load again (and again)?

I did, loaded up 15 and made first round hits on steel out to 900 yards.

 

[4xforfun]

I did, loaded up 15 and made first round hits on steel out to 900 yards.

That isn't the same as shooting 1/4 inch groups. Your "steel at 900" might be a dump truck!!

 

[joshb]

That isn't the same as shooting 1/4 inch groups. Your "steel at 900" might be a dump truck!!

Ouch!
Could have been a stack of shipping containers! 3 high and 2 long? But I bet it's a 12 inch plate. The "point" is that it would be nice to be more descriptive.

 

[jsthntn247]

We have 6,8 and 10" plates

 

[Ned Ludd]

Brad more than knows what he's doing. He was simply asking a question about a somewhat unusual result. In first reading this, my two guesses were 1) something might be loose and 2) for reasons that aren't clear to me, the pressure was spiking very quickly higher up and becoming erratic. Sounds like you've eliminated #1 as a possible cause with the subsequent tests. Did you record velocity data for the original charge weight test series? I'd be curious to know whether the 37.1 and 37.4 gr loads showed high ES/SD. A QL prediction using Varget/130s/26" barrel, calibrated for your velocity (2820 fps @ 26.3 gr) at 2.800 COAL shows pretty high pressure at 37.4 gr (>66,500 psi). Is this a new barrel by any chance? One that might speed up after a few more rounds? If not, it might just be on the slow side relative to others' barrels. In any event, it seems like the 37+ gr loads are definitely on the warm side.

 

[jsthntn247]

Ok, a few thoughts of my own. The 130 Norma's are longer that both 142 Sierra's and 140 Barnes match burners and have a longer bearing surface than both 140's. I believe what's happening is that they are basically 140's with 10 grains less weight, (similar to jlks,). Everybody shoots 140 hybrids at 37.3-37.5 and 2775,ish, so my identical 130's at 2815 is right in line. So, I got some 130 Hybrids and shot them today and they shot best at 37.7 and 2895 fps which is really close to what everybody else is seeing with the 130 Bergers. It seems the longer bearing surface of the Norma's is what was causing the issues, but still not sure why they went completely haywire unless my 8 twist was causing over rotation after a certain pressure or speed?