300RUM test

Thompsonj · Oct 21, 2024

I'm doing a little more testing with my 300RUM. I have nosler brass, CCI primers, 215gr berger and 81gr of Retumbo powder. I found the lands, and loaded 3rds each of .010 off lands, then went to .030,.050,.070. The 1st volley i shot was .010, I didn't think about it but I had a clean barrel. 1st shot was a bit higher the 2nd and 3rd shot, but 2nd and 3rd was close. One of the other loads was close like this one was. Should I reload 3 .010 off lands to see if it tightens up without the 1st shot being on a clean barrel?

Fullbore92 · Oct 21, 2024

I would just to verify if a clean barrel was the cause.

Thompsonj · Oct 21, 2024

Fullbore92 said:
I would just to verify if a clean barrel was the cause.

That's what I was wandering. I didn't even think about it being clean before I started

Shane Lindsey · Oct 21, 2024

Mine did the same thing yesterday. Few inches high for the cold/clean. I would recommend loading the same one again without cleaning and see where it's at.

I have about 700+ rounds on this barrel. When new, it would put the cold/clean into the subsequest group. Now it takes about four ro five to get it to settle down. I think the throat is pretty rough and the heavy fouling from the N570 helps to "fill" it in.

Brathany · Oct 21, 2024

Patch dry graphite through the bore after cleaning. It mimics a fouled bore and shot first shots don't wander POI.

Shane Lindsey · Oct 21, 2024

Brathany said:
Patch dry graphite through the bore after cleaning. It mimics a fouled bore and shot first shots don't wander POI.

Is it special graphite? I have some I use when necking up a wildcat, but not sure it is the same???

Brathany · Oct 21, 2024

Just "fine" bulk bags from Amazon. Last a lifetime I bet. It looks to be like the neck sizing graphite I had.

Shane Lindsey · Oct 21, 2024

I shall give it a go.

Brathany · Oct 21, 2024

Use some generic type degreaser, Purple Power, Gunscrubber, Acetone to bone dry the barrel after whatever cleaning chemicals and compounds used. You want it bone dry for the dry graphite, as not to clump.

I know for a hard fact this trick works. Once, I forgot to graphite my barrel. Bug hole shooting thing too. I forgot to graphite and went to the range thinking I did. First 3-4 rounds were outside the group and it wasn't until rounds 5-10 that I got back the gun I know. I was relieved when I discovered my error. If that isn't a blind test, I don't know what one is.

Thompsonj · Oct 21, 2024

This was another group i jad on a different jump.

Shane Lindsey · Oct 21, 2024

Don't be afraid to jump the 215s. I had a load for mine that had a max OAL of 3.745" to feed from an Accurate Mag. That was like an Evil Knieval jump to the lands, but it was pretty good. Looks funny though.

300RUM test

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