37 XC

[7mmmag]

I have a 37 XC with 34'' 1-8 twist barrel and am working up a load with 390 gr Badlands Bulldozers . The only powder I could get is VV N 570 so I loads 120-121-122 gr powder charges with bullet at the lands .


120 gr load cut each bullet hole but SD was 27 vel 2940 fps
121 got 2981 fps with same SD and group
122 was 2 '' group with vel of 3038 fps

What would cause this with the 122 gr load . I didnt clean the barrel for the 15 shots and the 122 gr was the last one . I would have not thought 1 grain would had that much difference or was it powder fowling ?

 

[SKWERLZ]

Brand new barrel?
Could be barrel speeding up, pressure spike, fouling or a combination of these.

 

[Terry]

You might clean the barrel and try again. It appears that the higher charge may be out of the node.

 

[7mmmag]

Yes it was a new barrel , when I cleaned it I did notice there was a lot of powder residue . I blamed some due to this , I have never shot any Vitivouri powder but the N570 seems dirty .

 

[CJ6]

Most ...If not not all 5 series VV powders I've used like the pressures on the high side to burn clean including 570.

 

[shooter74]

New brass? most are finding the node is around 2940 with 400 gr solids. My shooting buddy is getting well under 5 sd with 121 gr of n570.

 

[SKWERLZ]

New brass? most are finding the node is around 2940 with 400 gr solids. My shooting buddy is getting well under 5 sd with 121 gr of n570.

Nice to hear
I’m slowly putting together a 37 XC and I have lots of N570