40 Cal Sabotless Obturation Question

[chuck41]

Anyone recovered enough of these bullets to see how much they are actually filling the groves of our barrels when fired?

I have recovered parts of a couple and it appears that they were not really filling the groves very much at all. I was quite surprised at how shallow the rifling marks appeared to be on what was left of them.

[sw]

I haven't but will try.

[savagebrother]

yes, but they were 275 be's and even though they were completely flattened i had good graving of the jacket. the load was 65 grains of h 322.
sb

[smokeeter]

I also found that the rifling marks left behind were minimal on the heavier jacketed bullets like the nosler and the mag version of the XTP's (almost no existant). The regular XTP's and the SSTs had deep rifling impressions left in the copper, I'm sure it is a direct result of more obturation with the thinner jacketed bullets, accuracy was better also.

[chuck41]

Will be interesting to keep some track of this with different bullets to see how it might affect performance/accuracy. Shame it is so hard to catch them thangs to look at them afterwards.