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  • RumbleWepnz

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    Frommerstop,

    We could not get anything heavier than a 165 gr. bullet to stabilize in the 1 in 10 twist barrel. Since he was using a suppressor we preferred not to have the possibility of bullet tumble, so we opted to reduce the bullet weight by about 9%.

    This round was designed for a specific firearm for a specific purpose.

    Thanks for your interest though.
     

    kendive

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    Frommerstop,

    We could not get anything heavier than a 165 gr. bullet to stabilize in the 1 in 10 twist barrel. Since he was using a suppressor we preferred not to have the possibility of bullet tumble, so we opted to reduce the bullet weight by about 9%.

    This round was designed for a specific firearm for a specific purpose.

    Thanks for your interest though.

    Yes this is very important also. Took me over a year to get my two .308 subsonic loads for my Rem 700 TAC (1/10) 16" to be perfect. But it was fun getting there.

    One reason I use a very long 220 gr round noise bullet... I guess I just got lucky with the 180gr. LOL I am very happy with both of my subsonic loads using 700x.
     

    FrommerStop

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    Frommerstop,

    We could not get anything heavier than a 165 gr. bullet to stabilize in the 1 in 10 twist barrel. Since he was using a suppressor we preferred not to have the possibility of bullet tumble, so we opted to reduce the bullet weight by about 9%.

    This round was designed for a specific firearm for a specific purpose.

    Thanks for your interest though.
    That is surprising that a 1 and 10 twist would not stabilized a heavier bullet, but the holes in the target do tell the truth. The longer bullets at subsonic speeds probably tumble which will increase the lethality. But likely increases group size also.
     

    olecarver

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    Yes this is very important also. Took me over a year to get my two .308 subsonic loads for my Rem 700 TAC (1/10) 16" to be perfect. But it was fun getting there.

    One reason I use a very long 220 gr round noise bullet... I guess I just got lucky with the 180gr. LOL I am very happy with both of my subsonic loads using 700x.

    May I ask how many grains 700X you are using? to push the 180gr then how many to push the 220 grain? 700X was my multipurpose powder for .38sp. 9mm. and a few other,,, Thanks much olecarver
     
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    kendive

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    May I ask how many grains 700X you are using? to push the 180gr then how many to push the 220 grain? 700X was my multipurpose powder for .38sp. 9mm. and a few other,,, Thanks much olecarver

    220 gr Sierra Rn Nose 308 8.8gr 700x Mag Primer
    Series No 16
    Total number of shots 5

    Units velocity fps
    Units distances ft
    Units kinetic energy ft-lbf
    Units weight grain (gr)

    Stats - Average 1024.74 fps
    Stats - Highest 1048.8 fps
    Stats - Lowest 1012.99 fps
    Stats - Ext. Spread 35.81 fps
    Stats - Std. Dev 14.68 fps

    220 gr Sierra RN Nose 308 9gr 700x Mag Primer
    Series No 15
    Total number of shots 5

    Units velocity fps
    Units distances ft
    Units kinetic energy ft-lbf
    Units weight grain (gr)

    Stats - Average 1053.49 fps
    Stats - Highest 1066.62 fps
    Stats - Lowest 1035.06 fps
    Stats - Ext. Spread 31.56 fps
    Stats - Std. Dev 11.61 fps
     

    kendive

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    Some more data drilling out primer hole to 3/32 Total waist of time did not change anything. I also use oats and other fillers to take up the space in the .308 casing and another waist of time. Did not make a difference...

    NOTE: I use Mag Large Rifle Primers on all my .308 subsonic loads.

    Also note this was all taken with my Rem 700 16.5" 1/10 TAC. So the longer the barrel you will get slower speeds. Subs work just the opposite then full loads. Fulls loads you will increase speeds with a longer barrel.

    1 962 ft/s 8.5GR 700X 220GR Primer Hole 3/32
    2 923 ft/s 8.5GR 700X 220GR Primer Hole 3/32
    3 913 ft/s 8.5GR 700X 220GR Primer Hole 3/32
    4 910 ft/s 8.5GR 700X 220GR Primer Hole 3/32
    5 937 ft/s 8.5GR 700X 220GR Primer Hole 3/32


    Some 180gr Data

    11010 ft/s7.5GR 700X180GR
    21009 ft/s7.5GR 700X180GR
    31022 ft/s7.5GR 700X180GR
    41009 ft/s7.5GR 700X180GR
    51017 ft/s7.5GR 700X180GR
    61041 ft/s7.5GR 700X180GR
    71008 ft/s7.5GR 700X180GR
    81014 ft/s7.5GR 700X180GR
    91020 ft/s7.5GR 700X180GR
     
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    olecarver

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    Some more data drilling out primer hole to 3/32 Total waist of time did not change anything. I also use oats and other fillers to take up the space in the .308 casing and another waist of time. Did not make a difference...

    NOTE: I use Mag Large Rifle Primers on all my .308 subsonic loads.

    Also note this was all taken with my Rem 700 16.5" 1/10 TAC. So the longer the barrel you will get slower speeds. Subs work just the opposite then full loads. Fulls loads you will increase speeds with a longer barrel.

    1 962 ft/s 8.5GR 700X 220GR Primer Hole 3/32
    2 923 ft/s 8.5GR 700X 220GR Primer Hole 3/32
    3 913 ft/s 8.5GR 700X 220GR Primer Hole 3/32
    4 910 ft/s 8.5GR 700X 220GR Primer Hole 3/32
    5 937 ft/s 8.5GR 700X 220GR Primer Hole 3/32


    Some 180gr Data

    11010 ft/s7.5GR 700X180GR
    21009 ft/s7.5GR 700X180GR
    31022 ft/s7.5GR 700X180GR
    41009 ft/s7.5GR 700X180GR
    51017 ft/s7.5GR 700X180GR
    61041 ft/s7.5GR 700X180GR
    71008 ft/s7.5GR 700X180GR
    81014 ft/s7.5GR 700X180GR
    91020 ft/s7.5GR 700X180GR

    Reading this info, it sounds like you drilled out the primer hole for the test on 220gr loads ? A question are you setting the bullet as far out ,, to where it is barely off the lands of the rifling ? or are you setting them to book OAL ? and crimping? I have been told by some to load the bullet out as far as you can ,but don't hit the lands,, stay just off the rifling improves the load,,or have I misunderstood this ? Thanks olecarver
     
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    olecarver

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    IM going to set back an research,, a friend wants me to load Sierra 190gr HPBT Molly Coats, I been setting on a few yrs... Still following the thread Thanks gents
     

    kendive

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    Reading this info, it sounds like you drilled out the primer hole for the test on 220gr loads ? A question are you setting the bullet as far out ,, to where it is barely off the lands of the rifling ? or are you setting them to book OAL ? and crimping? I have been told by some to load the bullet out as far as you can ,but don't hit the lands,, stay just off the rifling improves the load,,or have I misunderstood this ? Thanks olecarver

    Yes I drilled out the primer hole on 10 pieces of brass to 2/32 and like I said that was a waist of time that made no difference. I would not recommend doing unless you just want to play around also. I got that idea from the great inner web but I don't believe anything out there unless I do it for myself.

    As for crimping and setting the bullets. I don't crimp at all and I just set the bullet to the normal OAL. I do rub very little paste case lube on each bullet before I set them. Nothing special going on here.

    The goals are to get as close as possible spreads on the Chrony's in a 5 to 10 shot group and if I can hit a 12" steel plate at 200 yards and the groups stay close on the plate with the subsonics. Also not break the sound barrier (tested at different alt and temps) I'm good. You can push the speeds up a little to maybe 1100 to 1200 but you risk breaking the sound barrier at different temps and alt. Trying to get that perfect medium. :)

    On the Chrony's I have used all at once the Labradar, Green Chrony F-1, and the Magnetospeed V3. Just to play and see if there is some major difference. They all work well and were very close to each other.

    I have since sold the Magnetospeed V3. So just down to the Labradar and Green Chrony F-1.

    Here is my Rem 700 I use for the Subs.

    yVNQrt1.jpg








    .
     
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    kendive

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    IM going to set back an research,, a friend wants me to load Sierra 190gr HPBT Molly Coats, I been setting on a few yrs... Still following the thread Thanks gents

    I think I had a few 190gr bullets I also did. I will dig up the data for ya. Found it!!!

    This was when I was first paying around and also had some Boxes of EBR subs that they sent to me for free to test. This first one is a bag of mixed rounds I collected some data on.

    Not sure if this will help you but may give you a start... Good Luck!

    1 1240 ft/s 190GR Bullet 9GR 700x
    2 924 ft/s EBR
    3 886 ft/s EBR
    4 897 ft/s EBR
    5 1233 ft/s 190GR Bullet 9GR 700x
    6 2736 ft/s Full 308
    7 983 ft/s EBR
    8 1236 ft/s 190GR Bullet 9GR 700x

    *********** Some more playing around also from 2016 ***************

    1 874 ft/s 190GR Bullet 6GR 700x

    1 821 ft/s 7GR 700X 190GR
    2 865 ft/s 7GR 700X 190GR
    3 863 ft/s 7GR 700X 190GR

    1 983 ft/s 7.5GR 700X 190GR
    2 999 ft/s 7.5GR 700X 190GR

    1 1014 ft/s 7.8GR 700X 190GR
     
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