pressure effect of swabbing bore with abrasive

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mtngun
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pressure effect of swabbing bore with abrasive

Postby mtngun » Sun Feb 10, 2008 5:52 pm

from the old forum:

3006 secondary spikes: effect of swabbing bore with abrasive

Here's the same 180 gr. loverin and 54.1 gr. Big Game load that is known to create huge secondary spikes.

Trace #1 is a "normal" shot, 2619 fps.

Then I brushed the barrel with copious quantities of JB's bore cleaner, and left the JB in the barrel. The theory was, JB would increase the friction and make the secondary spike go away.

Trace #2 is after swabbing with JB's, 2564 fps. Other than a slight drop in pressure and velocity, no change.

Trace #3 is another "normal" shot to clean the barrel, 2605 fps.

Then I brushed the barrel with copious quantities of 280 grit Clover compound, deliberately leaving the compound in the barrel. I expected the compound to increase friction, raise pressure, and make the secondary spike go away.

Trace #4 is after swabbing with Clover, 2614 fps. Nothing exciting happened.

Trace #5 is another "normal" shot, 2599 fps.
Image

This test was not very scientific, but if secondary spikes are caused by slippery bullets, why didn't the Clover change the spike? For that matter, why didn't the Clover compound do ANYTHING?

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