Welcome guest, is this your first visit? Create Account now to join.
  • Login:

Welcome to the NZ Hunting and Shooting Forums.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed.

DPT Terminator


User Tag List

+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 15 of 20
Like Tree5Likes

Thread: Has anyone had this problem?

  1. #1
    Valued Member 7mm Rem Mag's Avatar
    Join Date
    Dec 2016
    Location
    North Otago
    Posts
    1,870

    Has anyone had this problem?

    I worked up a load with AR 2217 powder and ELDX 162 gr bullets, I was using 171.5 gr of powder and it had a velocity of 2940 with nice groups some even tack drivers. I ran low on powder so got some more yesterday, I replicated the load and headed back to the range and to my surprise they were traveling at 3050 fps instead of the 2940 that I was getting the last time I went out and the groupings were terrible.
    I went home and broke the remaining loads down to double check I had put 171.5 gr's of powder which I had so now I am wondering if someone has slapped the wrong label on the new batch of powder as I have no other explanation for it.
    The only thing I can think of doing now is lighten off the load with the new powder to reduce it back to around 2940 fps and hope it comes back into tune. And I had 2 cony graphs going and they were both reading the same so it isn't a faulty machine.
    Thoughts please?
    When hunting think safety first

  2. #2
    Member
    Join Date
    Aug 2012
    Location
    Christchurch
    Posts
    4,413
    Its 71.5 not 171.5 is my first thought.

    2nd thought is look at the powder batches and report back. What chronograph did you use in both instances?

  3. #3
    Valued Member 7mm Rem Mag's Avatar
    Join Date
    Dec 2016
    Location
    North Otago
    Posts
    1,870
    Quote Originally Posted by PerazziSC3 View Post
    Its 71.5 not 171.5 is my first thought.

    2nd thought is look at the powder batches and report back. What chronograph did you use in both instances?
    Sorry, correct 71.5 gr I'll have to get back to you on the chronograph's 2 different types but not mine and I'll have to get back to you on the batches as they are not at my place. Can get that info tomorrow. Thanks for the reply.
    When hunting think safety first

  4. #4
    R93
    R93 is offline
    Member R93's Avatar
    Join Date
    Feb 2012
    Location
    Westland NZ
    Posts
    16,102
    Did you clean the barrel between outings?
    If not I'd say you could have a copper issue.
    Was there any real difference in temperature as that could effect all sorts including the chronographs.


    Sent from my SM-G965F using Tapatalk
    Do what ya want! Ya will anyway.

  5. #5
    Valued Member 7mm Rem Mag's Avatar
    Join Date
    Dec 2016
    Location
    North Otago
    Posts
    1,870
    Not thoroughly so I am in the process of doing that right now, thank you for that idea though as it gives me a glimmer of hope that it could be the problem but not sure why it would increase in velocity by 110 fps
    When hunting think safety first

  6. #6
    R93
    R93 is offline
    Member R93's Avatar
    Join Date
    Feb 2012
    Location
    Westland NZ
    Posts
    16,102
    Quote Originally Posted by 7mm Rem Mag View Post
    Not thoroughly so I am in the process of doing that right now, thank you for that idea though as it gives me a glimmer of hope that it could be the problem but not sure why it would increase in velocity by 110 fps
    Copper can/will increase pressure. But I would say coupled with different conditions on different days including light. How fast you fired your strings how warm or cold your barrel was reliability of said chronographs etc will account for the velocity and possibly accuracy issues.

    Sent from my SM-G965F using Tapatalk
    Do what ya want! Ya will anyway.

  7. #7
    Caretaker stug's Avatar
    Join Date
    May 2012
    Location
    Rolleston, Canterbury
    Posts
    4,850
    A velocity difference when you get a new tin of powder is common. Some powders are worse than others.

  8. #8
    Valued Member 7mm Rem Mag's Avatar
    Join Date
    Dec 2016
    Location
    North Otago
    Posts
    1,870
    Quote Originally Posted by R93 View Post
    Copper can/will increase pressure. But I would say coupled with different conditions on different days including light. How fast you fired your strings how warm or cold your barrel was reliability of said chronographs etc will account for the velocity and possibly accuracy issues.

    Sent from my SM-G965F using Tapatalk
    Ok thank you, I hope to give it another go tomorrow so fingers crossed
    When hunting think safety first

  9. #9
    Valued Member 7mm Rem Mag's Avatar
    Join Date
    Dec 2016
    Location
    North Otago
    Posts
    1,870
    Quote Originally Posted by stug View Post
    A velocity difference when you get a new tin of powder is common. Some powders are worse than others.
    Thanks @stug that's a bugger when you are chasing accuracy but good to know, would you recommend going down a grain or 2 to get back to 2940 fps to try to get it grouping well again?
    When hunting think safety first

  10. #10
    Gone................. mikee's Avatar
    Join Date
    Aug 2012
    Location
    Nelson, New Zealand
    Posts
    9,647
    Different batches of powder can have slightly different burning rates even if its the same powder. I try to buy enough of the same lot to not run out
    Other wise its a few grains out or in using a chrony to get the velocity "just right" like the batch before
    All those with dogs waiting no longer fear death. Those with many dogs waiting even welcome it in it's time.

  11. #11
    Valued Member 7mm Rem Mag's Avatar
    Join Date
    Dec 2016
    Location
    North Otago
    Posts
    1,870
    Quote Originally Posted by PerazziSC3 View Post
    Its 71.5 not 171.5 is my first thought.

    2nd thought is look at the powder batches and report back. What chronograph did you use in both instances?
    Chrony gamma master chrony plus an Oehler 35 T one in front of the other 3 meters from the muzzle
    When hunting think safety first

  12. #12
    Valued Member 7mm Rem Mag's Avatar
    Join Date
    Dec 2016
    Location
    North Otago
    Posts
    1,870
    Quote Originally Posted by mikee View Post
    Different batches of powder can have slightly different burning rates even if its the same powder. I try to buy enough of the same lot to not run out
    Other wise its a few grains out or in using a chrony to get the velocity "just right" like the batch before
    OK thanks for that, I may have to buy 2 or 3 at a time
    mikee likes this.
    When hunting think safety first

  13. #13
    ebf
    ebf is offline
    Mushroom juice ! Hic ! ebf's Avatar
    Join Date
    Jun 2012
    Location
    Above the Hutt
    Posts
    6,872
    Sounds like different batches of powder to me.

    Other thing to consider is if there were major differences in atmospherics between when you shot last and this test.

    What you want to record for a barrel is the muzzle velocity for a particular powder batch / weight combo.

    When you get a new batch, load some test rounds to make sure you are still in the velocity band that worked previously (called a node).

    Depending on how much you shoot, buying powder in bulk is well worth it for consistent results. For fullbore I tend to buy powder in 4kg bottles, and that is not exactly a busy season...
    Viva la Howa ! R.I.P. Toby | Black rifles matter... | #illegitimate_ute

  14. #14
    Member
    Join Date
    Jul 2013
    Location
    Godzone, South Island
    Posts
    1,705
    Ive had the same thing at times, ammo was in the back of the truck for the day, and was warmer than the last time. Now I usually bury my ammo in the coldest part of the truck and dont leave it in the sun as Im using it.
    7mm Rem Mag likes this.

  15. #15
    Valued Member 7mm Rem Mag's Avatar
    Join Date
    Dec 2016
    Location
    North Otago
    Posts
    1,870
    Quote Originally Posted by ebf View Post
    Sounds like different batches of powder to me.

    Other thing to consider is if there were major differences in atmospherics between when you shot last and this test.

    What you want to record for a barrel is the muzzle velocity for a particular powder batch / weight combo.

    When you get a new batch, load some test rounds to make sure you are still in the velocity band that worked previously (called a node).

    Depending on how much you shoot, buying powder in bulk is well worth it for consistent results. For fullbore I tend to buy powder in 4kg bottles, and that is not exactly a busy season...
    OK thank you, I had never heard of that before
    When hunting think safety first

 

 

Similar Threads

  1. die problem?
    By northdude in forum Reloading and Ballistics
    Replies: 8
    Last Post: 15-01-2016, 06:03 AM
  2. Dog with a little problem
    By Chris in forum Hunting Dogs
    Replies: 18
    Last Post: 14-05-2012, 08:15 PM
  3. Dog with a little problem
    By Chris in forum Dogs
    Replies: 18
    Last Post: 14-05-2012, 08:15 PM

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Welcome to NZ Hunting and Shooting Forums! We see you're new here, or arn't logged in. Create an account, and Login for full access including our FREE BUY and SELL section Register NOW!!