Quick question, root cause of 2 + 1 groups?

[Barbourcreek]

after our discussion I believer barrel is the culprit Single heat stress walker !

 

[Varmint Hunter]

I did something very similar except that I used a .223 case with the base drilled out. I slipped a surgical (like) rubber tube over the base of the case. The tube is very flexible and the case easily slips into any size chamber.

 

[Darryle]

Darryle,
I don't recognize that device. Would you mind elaborating on it? I am currently using the magneto speed riflekuhl and although it works and is nice and compact, it takes longer than I like
thanks,
Jim

It's a rechargeable air mattress pump similar to this one.

Rechargeable Air Mattress Pump