woodwose, on Jan 1 2009, 01:36 PM, said:
The Tom Kaye Barrel article
suggests that the optimal barrel length for efficiency is 8-10 inches, and that the effective length of a barrel is the length only until the porting begins. It is very cool that this test verifies this article, since this has basically become the current conventional wisdom on barrel length vs. efficiency.
Also, where do you get Grain Belt beer? Is that midwest thing?
we've actually disproven this idea now. The CP .683 back without a front was significantly slower than with the 10" tip - and that tip has porting for nearly all of the length. This indicates that the ball is still accelerating through at least some of the ported portion of the barrel.
And yes, grainbelt is a Minnesota thing. It's a beer that was brewed in Minneapolis right across the river from downtown starting in the 1890's. In the 40's Grainbelt Premium was introduced - it changed hands a few times and went away in the 70's - but a brewery called Schells in southern Minnesota started producing it from the same recipie in 2002. This sign
is a classic landmark on the river in downtown Minneapolis.
woodwose, on Jan 1 2009, 01:44 PM, said:
The 1 piece barrel is more efficient (290.25 vs. 276.95) but less consistent (5.73 vs. 4.70). This seems to validate the theory that a 2 piece barrel does most of the acceleration of the ball in the first 5 inches (or whatever the length of the back is) instead of the full 12 inches of barrel length, so therefore there is less barrel length that can act on the ball (via friction that magnifies the ireegularity of the paint) and cause variation in velocity. Do you guys agree with this?
I can't wait to see the accuracy test. I would also like to see a Palmer barrel in there since that is the only other significantly different barrel design besides 1 piece, 2 piece, and rifled. That could be test 3 - where you test the effects of barrel porting
yes, we agree that a majority - but not all - of the acceleration seems to happen in the first part of the barrel. We looked at the two piece with an underbored back this way: it gained the consistency of an overbore via the tip - but kept much of the efficiency of an underbore with the back. Sort of a best-of-both situation. Once we have the accuracy data then the decision between one and two piece may become more clear.
As to the Palmers - yeah, that would be cool to add, if anyone has one to lend for a test - we would love to give it a try. The nice thing about this test is that once we've got good baseline testing procedures set up we can get a good comparative test with a pretty small test. In other words - once we know how the barrels we have rank - we can then setup a new test, include some known barrels and add some new ones - and get a pretty good idea about how the new ones fit into the old data.