17 Hmr ..... ammo mods.

Discussion in 'Rimfire Forum' started by es 350, Aug 11, 2018.

  1. es 350

    es 350

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    Jun 28, 2014
    First off a word of CAUTION..... I DO NOT recommend any one try this without proper saftey precautions!!!

    Running ballistics on 17 gr and 20 gr 17 cal v max bullets you can see the advantage of the higher b.c. 20 gr.

    Even though factory loads are available with 20 gr h.p. bullets , because of h.p. design offer no b.c./range over 17 gr tipped bullets.

    So.... I picked up a box of 20 gr v max bullets to experiment......

    First I machined an adapter for my bullet puller, this did not work as it also " pulled" the priming mixture from case..... next I machined a sleeve with over size hole for loaded round to fit into, oversize so it could move and not put undo side force on case neck when pulling bullets.

    With a way to now have primes cases I experimented a bit with several powders, aa9, 300mp , h-110 and L.S., all of which seemed they would work well in 17 Hmr.

    Have read Hmr is loaded with lil-gun from factory.....? did not try or compare(yet) but decided to use powder from pulled rounds.
    Factory 17 gr loads have 5.4 gr of ? fine ball powder. I dropped this to 4.5 gr to start with the 20 gr v max, result was little over 2000 fps. I worked up to the 5.4 gr for an av. Velocity of 2472 fps.
    Have seen this velocity from factory 20 gr loads and no signs of excssive pressure IN MY RIFLE!
    My rifle is custom built (in progess)by myself with a tight chamber from a reamer I also machined.
    It is a drop block action with a bull barrel with FULL chamber support of the brass!
    Some bolt action 17 Hmr's do not !!!!!

    Would be nice if factory loads were available with the 20 gr v max!
    I thought they were at one time....?

    Below is some pics comparing the 17 gr factory load with my "reloaded" 20 gr. and ballistics of 17 gr @2600 fps and 20 gr @ 2470.
    17 gr @ 2600
    20 gr @ 2470

    The little testing of accuracy so far shows the 17 gr to be more accurate in my 1-9 twist barrel, 17 gr Fed. Or Hornady factory loads shoot in the low .1's for 3 shots @ 50 yds.

    The only group fired with 20 vmax was .198 ctc for 3 [email protected] 50 yds, while not bad hopefully can be improved on.
    Last edited: Aug 11, 2018