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Thread: PR Bullet duplex sabot

  1. #21
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    Big Jack

    Really canít say anything about a kit that utilizes large rifle primers as I have no experience with them.
    Utilizing the large rifle primer kit I wonder how long those modules last.
    Then thereís always the priming and de-priming modules as an extra step.
    Preferring a simple setup of placing a 209 into the carrier on the bolt head and seating it into the BP is more to my liking.

    The best improvement I got with consistent ignition was recessing the vent into the BP about 5/8Ē also creating a smaller diameter powder chamber. The only extra machining I need to do with the vent is reducing the head diameter to 5/16Ē to match the recess diameter.
    Also my head spacing is adjust for a good close fit so no blow back or primer bulging.

    Have played with H322 before BP modification but always found unburned powder at muzzle. This is using a 250gr bullet because Iím not a fan of 300gr bullet.
    A suggested load for REL-7 and 250gr bullet using 63-69grns is another load I want to eventually try instead of H322. 69gns of REL-7 should put you at about 2450fps plus.

    As many years Iíve owned a 10ml-II and even with the amount Iíve learned there is still more yet to learn even for me. Just finding the range time and access is the awkward part.
    Definitely a lot of fun experimenting and learning with a Smokeless Muzzle Loader.


    Ed

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  3. #22
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    While going through my 10ML-II files I reviewed my original notes on duplex sabot experimenting to refresh my memory. Here is a picture of my setup with sabots.
    40-50 200SW Load A.jpg

    In order to get a proper fit with the inner sabot I machined the cup off for a good contact seating using a chuck I made.
    Sabot Base Trimming Tool B.jpg

    Up to roughly 2000fps I got a so so response for accuracy. After that it was like a shotgun pattern. Also after 2000fps I could only locate the outer sabot and not the inner sabot. It was as if the inner sabot did not release from the bullet. I momentarily stopped here experimenting and began at looking how to bond the 2-sabots to release as one. Surprisingly there is no glue that will properly bond this type of plastic and fusion with heat is the only way.
    Note: Some might ask why not use the 40/50 sabot available. It is not a high pressure formulation and again when you reach around 2000fps they begin to fail. If they ever come out with a high pressure formulation then I wouldnít waste my time with sabot duplexing.

    During this time I noticed that Hornady came out with the 200FTX-.452Ē diameter and momentarily switched gears for my quest of a high velocity 200gr bullet. Here I hope to push the velocity with the 200gr FTX accurately before returning to sabot duplexing. The .400Ē 200SST should hold up better to fragmentation than a .452Ē bullet.

    Anyway this is just a brief history of trying to get a 200gr bullet to perform in a 50Cal 10ML-II. For the moment it is on the back burner because of other priorities to deal with. Somewhere down the road it will again appear on the main menu.
    By that time I should have also replaced some of my hair follicles that I ripped out with this experimentation.
    As for how PR manages a duplex sabot load I haven't got a clue.

    Ed

  4. #23
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    Quote Originally Posted by ET1 View Post

    Note: Some might ask why not use the 40/50 sabot available. It is not a high pressure formulation and again when you reach around 2000fps they begin to fail. If they ever come out with a high pressure formulation then I wouldn’t waste my time with sabot duplexing.
    Ed
    First off, Ed and Jack, thanks for all the info on this thread I do appreciate the read.
    But, Yes, I'm one of the ones that has to ask...

    Trying not to get too convoluted and using rough numbers to illustrate the point, my confusion lies in the ‘why’ because it seems that there are easier ways to achieve the same end result, at least in terms of accuracy.

    Using a standard .40/.50 sabot combination , with a 200 gr Dead Center, with 110 gr T7 it will give me 1550 ft/s at 250 yds with a drop of -6.7 (zeroed at 200)

    Using a duplex sabot with a .357 195 gr Dead Centre with 120 gr of T7 will give be 1776 ft/sec and a drop of -5.2 (zeroed at 200)

    So roughly, using a smaller bullet and a duplex sabot, I will gain in terms of accuracy, about 1.5” trajectory.

    Would it not be simpler to adjust the elevation 'clicks' on the reticle to raise the trajectory of the 200 gr bullet to match the trajectory of the .357 bullet. ?
    Last edited by MikePal; December 13th, 2014 at 09:40 AM.
    Arte et marte (By Skill and by Fighting)...The RCEME motto

  5. #24
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    MikePal

    Nothing wrong in asking questions or expanding discussions.

    Now I have to ask, where did you get these figures?
    Do you have any muzzle velocity figures to share?
    Have you actually shot any distances to verify or proof these figures?
    For these mentioned bullets would you have any BC ratings so that a base line velocity can be calculated to match that bullet drop?


    Ed

  6. #25
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    MikePal

    Iíve answered my own questions by paying a visit to PR site.

    http://www.prbullet.com/bal.htm

    Read down this page and see how they determine BC for their bullets by using the highest calculated BC. If real time shows less they wonít publish this BC. I call that misleading BS.

    http://bulletin.accurateshooter.com/...tics-software/

    I use the above program to verify actual BC from range results and review characteristics of loads before testing sometime.
    I find it to be a simple handy tool to have.



    Ed

  7. #26
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    The question still remains....wouldn't it be simpler to adjust the reticle to compensate for a heavier slower bullet to achieve the same accuracy (point of aim) as a faster lighter bullet. ie; if one has a drop 1.5 " greater than the other, why not just adjust the elevation (trajectory) ?
    Arte et marte (By Skill and by Fighting)...The RCEME motto

  8. #27
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    MikePal

    In this case I canít give you a definitive answer because it depends upon the shooter how he adjusts to his particular bullet drop for his load.
    That first involves where he wants his zero point for what he considers his best MPBR which is what I do. After that I make no further scope adjustments even to compensate any difference at a further specific range because my shooting doesnít involve a fixed range area.


    Ed

  9. #28
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    I am chasing as fast and flat a round as possible.

    When I look at duplex loads and Duplex sabots, I hope to be pushing around the 2600 -2900 fps range with a 200 grainier.

    There are existing loads to 2600 fps using a 250 grain bullet.

    The goal is having a useable range of 0 to 300 yards.

    Keep in mind I am already driving a 260 grain bullet right around the 2300 fps mark and am not satisfied that it will carry to 300 with a good enough/useable trajectory.

    I see deer at 300 plus yards where I hunt so hopefully you can understand my goal.

  10. #29
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    Quote Originally Posted by ET1 View Post
    While going through my 10ML-II files I reviewed my original notes on duplex sabot experimenting to refresh my memory. Here is a picture of my setup with sabots.
    40-50 200SW Load A.jpg

    In order to get a proper fit with the inner sabot I machined the cup off for a good contact seating using a chuck I made.
    Sabot Base Trimming Tool B.jpg

    Up to roughly 2000fps I got a so so response for accuracy. After that it was like a shotgun pattern. Also after 2000fps I could only locate the outer sabot and not the inner sabot. It was as if the inner sabot did not release from the bullet. I momentarily stopped here experimenting and began at looking how to bond the 2-sabots to release as one. Surprisingly there is no glue that will properly bond this type of plastic and fusion with heat is the only way.
    Note: Some might ask why not use the 40/50 sabot available. It is not a high pressure formulation and again when you reach around 2000fps they begin to fail. If they ever come out with a high pressure formulation then I wouldn’t waste my time with sabot duplexing.

    During this time I noticed that Hornady came out with the 200FTX-.452” diameter and momentarily switched gears for my quest of a high velocity 200gr bullet. Here I hope to push the velocity with the 200gr FTX accurately before returning to sabot duplexing. The .400” 200SST should hold up better to fragmentation than a .452” bullet.

    Anyway this is just a brief history of trying to get a 200gr bullet to perform in a 50Cal 10ML-II. For the moment it is on the back burner because of other priorities to deal with. Somewhere down the road it will again appear on the main menu.
    By that time I should have also replaced some of my hair follicles that I ripped out with this experimentation.
    As for how PR manages a duplex sabot load I haven't got a clue.

    Ed
    Thanks for this info Ed!

  11. #30
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    Big Jack

    I can appreciate your goal but consider this chart.


    250gr bullet 2600fps.JPG


    A 250gr SST using a BC of .18 (value my testing revealed) doing 2600fps still has slightly over 1000ft/lbs at 300yds which is more than enough to take down a deer. If 150yd zero is used you have about 20Ē drop at 300yds.
    Again something to consider.


    Ed

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