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Barrel velocity from 30 to 34

Discussion in 'Uncategorized Threads' started by Wayne of PA, Dec 26, 2007.

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  1. Wayne of PA

    Wayne of PA Member

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    I’ve been shooting trap with 30 inch over and under barrels for a number of years now and I am considering buying a new shotgun with a 34 inch unsingle barrel. Will my velocity increase with a longer barrel?

    Thanks,

    Dale,
     
  2. mixer

    mixer Well-Known Member

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    Slightly but not enough that you would notice.


    Eriv
     
  3. Neil Winston

    Neil Winston Well-Known Member

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    I tested one 34 against a bunch of 30's and what I got is in the attached link.

    One is not enough to draw any conclusions from, but it's something.

    Neil
     
  4. lumper

    lumper TS Member

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    No ... it will not.

    Yes ... it will.

    Take your pick cause you will get both answers but overall it wont change any at all that you will notice or that it will effect your shooting.
     
  5. FarmerD

    FarmerD TS Member

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    I have a Model 12 trap with 30 inch full choke barrel that shoots about 25 fps slower than my MX-10 RS with factory full choke, same shells, same chronograph. Ben
     
  6. BDodd

    BDodd TS Member

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    I've not made the test in any scientific manner but I've seen the likelihood that higher temperatures will increase velocity readings, tightness of choke will increase velocity readings, and length of barrel will increase velocity readings all over a home-owner style chronograph (Oehler). But the individual differences are not a lot different than the normal spread of samples within any one group of shells so chronographed. Do the 30" barrels one day and the 34" barrel the next; do the same barrel one day and repeat it another; or change guns in the middle of a test and the spread may go one way or the other. Now, compare an 18" cylinder bore against a 34" full choke and you'll see that there certainly is a difference that will likely be repeated.....breakemall....Bob Dodd
     
  7. Wayne of PA

    Wayne of PA Member

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    Thanks for all the replies. It sounds like in most cases the velocity will slightly increase like Neil mentioned in another thread.

    I guess after I buy the my gun I could do my own testing. I’ve always wanted a chronograph. What inexpensive chronograph would you suggest? I noticed Gamaliel has an RCBS for $90.00. Of course the shells will all have to be reloaded exactly alike. It could be interested. Thanks,

    Dale,
     
  8. BDodd

    BDodd TS Member

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    Dale, first recognize homeowner chronographs are designed to deal with a single pellet or bullet as in a rifle, handgun, or even an arrow. They are not terribly accurate with shot shells since they will be reading the leading pellets out of the barrel at the first or start screen and again at the stop stop screen ignoring the fact that there is actually a swarm of pellets and most of that swarm is behind those leading pellets. After a lot of grief and pondering myself, I've learned to take a reliable factory load to the field and run it through my gun, my barrel, and my preferred choke at the same temperature and weather conditions and then use that data to compare my handloads for the day. If my handloads are give or take 10 fps faster or slower than the reading for the factory shells, I'll likely consider them quite similar to the factory load. If I'm trying to match that factory load and the differences are in the 20s or 30s one way or the other, then it's back to the loading room for some changes. So, don't hesitate to have a chronograph and use it but use it as a comparative tool rather than thinking it's going to give you precise data as could be gotten from a very expensive test barrel and inductive chronograph that the powder companies would use to publish reliable recipes....breakemall....Bob Dodd
     
  9. phirel

    phirel TS Member

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    At this time, I am not ready to accept that a 34 inch barrel will shoot harder than a 30 barrel. I don't have any good data to support my position. But, the data given by Neil, at least as presented, does not indicate that I am wrong.

    Consider these hypothetical velocity tests: same shell through a 30 inch barrel gave the following velocities- 1180, 1190,1200. And the same shell through a 34 inch barrel gave these velocities-1190, 1200, 1210. The average of these two sets is different but some simple analysis will tell us that there is no difference between the velocities shot through 30 and 34 inch barrels in this test.

    Pat Ireland
     
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