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  1. #1

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    6.550SR Japanese

    Pre-written work here that presumes a level of knowledge......it may even be almost a wildcat and casting post but I parked it in rifles because I don't shoot much of the new wizbang stuff and even the popular ones are in well worn platforms .

    In an effort to change things up a little;

    Extraordinary efforts to get things running in a mediocre QC 95 yr old foreign milsurp that has occasionally available brass but a somewhat oversized and not terribly unusual groove dia . It is called a 6.550 Semi Rimmed and in a Type 38 Arisaka of Imperial Japan . Research says it was assembled in 1927 . I took a picture but it was so ugly it broke the camera lens .

    Cast or paper patched is the only way this gem has any hope of shooting well as the Metford type rifling is shallow , round and .266.270 with a throat and leade that will take a .272 over .1 out of the case .

    I had an associate make a Lee style push through sizer at .2728 and an H&I for the Lyman 45 at .273 . Another associate hearing of my woes helped me out with a bushing type neck sizing die , the needs fell into a bushing dia void to get me . 001-3 neck sizing . I ended up with 3 bushings which works out because to form brass from 308 family neck thickness varies a lot even with reaming necks .
    I have a Big Max A4 so swaging the 243 shown down from .473 to the needed .458 head is a half stroke relube full stroke affair . The rim remains .473 . I've had the good fortune of accumulating 60+ Norma cases but they rattle until fire formed .

    The last bug seems to be the , even for myself , bizarre seating die adjustment to accommodate the nose of the 27-135 FN RCBS . It appears that the nose and bands are larger than the crimp step so my first dummy lodged the bullet in the seating die . I backed the die out about 4 turns , then 4 more , back down 2 , fiddle. The case neck now just flattens the flair and the driving band stops against the seating stem just below the crimp step . I did mangle 4 bullets to figure it out .

    So I have 2 custom bullet sizers , a custom neck sizing die with 3 otherwise unavailable bushings and a rifle that will get a one or two of its own bullet moulds .

    I have an NOE 270-140 that drops a .272 and a 266469 that shows some promise sized .265 and patched up to .272 . Unfortunately all work was stopped for most of a year due to pre owned brass failures .

    I have about 75 smackers more than the gun is worth in tools to shoot it. Good thing factory ammo rides over the lands shoots like crap and costs $2.25 a shot or this wouldn't be worth the effort .
    6045~2.jpeg


  2. #2
    JeffreyDeGraff's Avatar
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    That is truly a labor of love. I admire your willingness to go the extra mile to make things like this happen. I sure would love to see a picture of this ugly rifle, I would probably think its not so ugly. Please post an update after you shoot. Im very curious.


    JTD


  3. #3

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    Probably about Labor Day .
    I got a bunch of wood to cut . But my work schedule is going to settle down to regular days and hours instead of just checking the schedule to see when I need to show up next .


  4. #4
    JeffreyDeGraff's Avatar
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    Ill be looking for the follow up. Glad your work is going to settle down.


    JTD


  5. #5

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    Today is almost a milestone day . I sized my very first bullet in a lube/sizer . It's kind of a big deal, I've only been casting about 15 years and I learned paper patch to avoid using gas checks ....... Which was kind of dumb as I ended up buying push through sizers for the cores anyway .......
    I think I'm going to like this tool it does save a step or 2 over the push through dies and once set up and ports blocked for select groove lubing and avoiding lube spooge it is a little faster than thumbing .

    I sized and checked 25 RCBS 27-130FN to fire form a box of new correct brass and 5 formed from 243 . I had enough WWII surplus repacked H4831 left for about 30 rounds so that worked out for me .

    In the 6.550 both IMR and H4350 and H4831 are max case capacity powders based on my books with data circa 1959-1978 if it'll keep the bullet in the case it's okay to have that much in there . 35.0 it is , works out it's a little over a start load and what the measure was set at for the Ken Waters pet loads 500 gr 45-70 load I did last . These should be around 42-45 kpsi .

    They are gas checked with aluminum checks from Sages outdoors, not to be confused with Sages reloading . The aluminum checks are about 2/3s the cost of copper and as near as I can tell don't have any real handicap vs copper .

    I'll shoot these for groups of course and if I'm on my toes over the chronograph . Being honest I don't expect much at this point there's still some dark spots in the barrel and my eyes aren't what they once were . The sights are are a triangle in a V with a 100 meter basic 200 meter flip up in 200 meter steps to 2000 meters. There's no face contact with the stock past about 1000 meters .
    The BC of most of the 140 gr cast bullets will likely require "full post" sighting or possibly even using the 200 meter flip up for 100-150 yd zeroes . As a result I'll shoot these 25 at 50 yd on big targets .

    Previous trials with naked cast and some gifted PC bullets gave me groups from 86" (no I didn't skip a decimal point that says 7 feet) and bullet profile holes to that shows some promise .......now what was my hold and was it consistent or is that last 2" me ......at 50 yd . Also I had make do sizers that were really only useful for the paper patch core and installing gas checks on grossly over sized bullets for the task . Hopefully with more correct and accurate sizing it will be better .

    At some point I will need to come up with a 7-08 seating die as the neck and crimp step are "fixing" the swollen noses on the bullets I sized base first in the Lee dies the set the gas checks . It won't hurt anything except that the die also hits the front band on the neck to shoulder step .

    I'm working with a bullet that to fill the bore and throat is as large as the OD of the neck expanded to hold a .266 dia bullet .

    The current barrel dimensions would allow a .264 jacketed or even copper bullet to strip the lands a situation compounded by the Metford type rifling that resembles a torx head that in this case is .271.264 . Mostly .


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