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.

Terminator DPT


User Tag List

+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 15 of 22
Like Tree40Likes

Thread: Seating depth dilemma

  1. #1
    Member mopheadrob's Avatar
    Join Date
    Jun 2018
    Location
    Christchurch
    Posts
    695

    Seating depth dilemma

    Starting out loading for my Model 7 7mmWSM. Projectile of choice is 150gr. ABLR.

    Measured the max. cartridge base to ogive length for my chamber using the split-neck case method and got 2.305”. That seems really long - the factory Precision Hunters are 2.185” CBTO and they’re too long for my magazine.

    Until measuring, I thought the PH’s were too long for the chamber as well because the bolt is really stiff to close on them. I assumed I was jamming them into the lands, because I don’t get that with Fed Fusions or PowerShoks.

    Back to the ABLRs…To fit the mag I’d need to seat them to 2.175” CBTO. That’s 0.130” jump. Seems way too much to me. I could single-feed until I can get the magazine modified…

    I was planning to start at 0.040”, so 2.265” CBTO. That puts only 0.265” of bearing surface in the neck though, so I need to add 0.020” to achieve the rule-of-thumb of at least the calibre.

    Where do the forum gurus think I should start? 0.060” jump, 0.130” or somewhere in between?

  2. #2
    Almost literate. veitnamcam's Avatar
    Join Date
    Dec 2011
    Location
    Nelson
    Posts
    24,972
    Id start at mag lenght and work back....who knows it may just shoot
    "Hunting and fishing" fucking over licenced firearms owners since ages ago.

    308Win One chambering to rule them all.

  3. #3
    Member
    Join Date
    Jun 2021
    Location
    huntly
    Posts
    753
    Unless you don't want to use you mag and turn your rifle into a single shot don't seat over the recommended COAL, even if that means a .130" jump. I don't know exactly what the jump is in 303's but I'm sure its more than .130", depending on projectile.
    Moa Hunter and mopheadrob like this.

  4. #4
    Member
    Join Date
    May 2012
    Location
    Sydney
    Posts
    1,632
    Start at mag length.
    Micky Duck, rewa, dannyb and 1 others like this.

  5. #5
    Member
    Join Date
    Feb 2020
    Location
    Scotland
    Posts
    1,214
    Use jump friendly bullets, can't say what they are yet as I've just started with 7mm's myself but considering how jump tolerant some projectiles like Barnes are, I would not worry too much.

    Furthermore, since it's a Mod 7, I'd be inclined to stick with what the mag box can fit (2.8" odd IIRC), didn't think you could extend them much more!
    rewa and mopheadrob like this.

  6. #6
    Member stagstalker's Avatar
    Join Date
    Jul 2018
    Location
    North Island, New Zealand
    Posts
    2,190
    The ABLR from common reporting seems to be a fussy projectile that often doesn’t like being close to the lands anyway. Try them at mag length and see how you go.
    Micky Duck, rewa and mopheadrob like this.

  7. #7
    Unapologetic gun slut dannyb's Avatar
    Join Date
    May 2018
    Location
    Oxford, North Canterbury
    Posts
    9,209
    Have just gone through this with my 7mm08 mod 7 I didn't even bother measuring maximum CBTO as I new I wouldn't get anywhere near it with the limited mag length of a mod 7.
    I also dont think there is much if any more length to be gained by modding the mag box.
    Another issue you will have with using a long projectile like the ABLR is that to seat it at mag length it will take up room in the case limiting powder capacity.
    That being said my 708 using 150gn eldx seated at mag length shoots fantastic so it is possible you may get the ABLR to shoot even with a big jump.
    If the ABLR don't work mabey the eldx would be worth a shot, whatever pill you use I dont think you will be able to seat it anywhere near the lands without single feeding due to the short mag length of the mod 7.
    That shouldn't stop you from getting awesome results.
    Micky Duck, rewa and mopheadrob like this.
    #DANNYCENT

  8. #8
    Member
    Join Date
    Dec 2019
    Location
    Okawa Hawkes Bay
    Posts
    3,070
    Quote Originally Posted by mopheadrob View Post
    Starting out loading for my Model 7 7mmWSM. Projectile of choice is 150gr. ABLR.

    Measured the max. cartridge base to ogive length for my chamber using the split-neck case method and got 2.305”. That seems really long - the factory Precision Hunters are 2.185” CBTO and they’re too long for my magazine.

    Until measuring, I thought the PH’s were too long for the chamber as well because the bolt is really stiff to close on them. I assumed I was jamming them into the lands, because I don’t get that with Fed Fusions or PowerShoks.

    Back to the ABLRs…To fit the mag I’d need to seat them to 2.175” CBTO. That’s 0.130” jump. Seems way too much to me. I could single-feed until I can get the magazine modified…

    I was planning to start at 0.040”, so 2.265” CBTO. That puts only 0.265” of bearing surface in the neck though, so I need to add 0.020” to achieve the rule-of-thumb of at least the calibre.

    Where do the forum gurus think I should start? 0.060” jump, 0.130” or somewhere in between?
    Greetings mopheadrob,
    I have a Remington 700 Sendero in 7mm SAUM that I regrettably have not done much with. I have measured the cartridge overall length for a number of projectiles with them touching the rifling. Max to seat in the mag is 71mm.

    Remington corelokt 150 grain. Crush length 72mm. Jump 1mm
    Hornady 139 grain Interlock. Crush length 72.25mm. Jump 1.25mm
    Hornady 139 grain SST. Crush length 73.5mm. Jump 2.5mm.
    Speer145 grain SP. Crush length 74.5mm. Jump 3.5mm.
    Hornady 162 AMax. Crush 75mm. Jump 4mm.
    Nosler LRAB 150 grain. Crush 76.2mm. Jump 5.2mm.

    I note that the ogive is barely out of the case mouth when seated to mag length with the LRAB in your rifle and has minimal seating depth when loaded close to the rifling. Lengthening the mag will only fix one of these problems. Perhaps a different projectile could be considered depending on the use you have for the rifle.
    Regards Grandpamac.
    dannyb and mopheadrob like this.

  9. #9
    Member Mathias's Avatar
    Join Date
    Oct 2015
    Location
    Canterbury, home of the big Rakaia Red Stag
    Posts
    4,513
    LRAB's like a jump, don't worry about it and work on a mag length that feeds well.

  10. #10
    Member
    Join Date
    Mar 2018
    Location
    Fielding-ish
    Posts
    572
    I had a hard time making .222 accurate with reloads. Unheard of eh, you cant Make a .222 inaccurate, so they say. It was accurate with Privi, so I copied their length ogive-to-lands, and it shoots lights out. Miles bigger jump than All the 'experts' (all across the Planet) are saying. Forget about 'the-jump', and go with what works ,with all the tips that others have given above.

  11. #11
    Member Micky Duck's Avatar
    Join Date
    Apr 2015
    Location
    Geraldine
    Posts
    24,797
    Quote Originally Posted by rewa View Post
    I had a hard time making .222 accurate with reloads. Unheard of eh, you cant Make a .222 inaccurate, so they say. It was accurate with Privi, so I copied their length ogive-to-lands, and it shoots lights out. Miles bigger jump than All the 'experts' (all across the Planet) are saying. Forget about 'the-jump', and go with what works ,with all the tips that others have given above.
    funny as heck...SOME of us use a factory load that rifle likes and set up seating die using that...and have done so for 30 years......


    if you want close to lands ,and within mag length,use a round nose LMFAO.....
    mopheadrob and caberslash like this.

  12. #12
    Member
    Join Date
    Jul 2019
    Location
    Hamilton
    Posts
    246
    Try mag length and see how they go. My model 7 saum shot the 168vld’s and 160tmk well at mag length/jumped, better than when I tried to seat them long. There is very little length to be gained trying to extend the mag box in the model 7, looks more hassle than it’s worth. I’m about to work up a load with the 162eldm in a barrel I just got fitted, and going to start seating them 10thou off for a ladder to find pressure, then push them deeper and see how that goes.
    Cheers
    mopheadrob likes this.

  13. #13
    Gkp
    Gkp is offline
    Member
    Join Date
    May 2018
    Location
    Queenstown
    Posts
    1,831
    It's fine to jump .130
    I don't have experience jumping the lrabs that far but I know the eldms are not finicky on the jump
    mopheadrob likes this.

  14. #14
    Member mopheadrob's Avatar
    Join Date
    Jun 2018
    Location
    Christchurch
    Posts
    695
    Thanks all - seems to be a pretty clear consensus there. Yes @grandpamac, I noticed the projectile was in pretty deep at mag length and wondered about case capacity and also the problem discussed in the recent “loose projectile” thread.

    The rifle is intended to be a longer range tops / tahr hunting rig, hence the pointy projectiles. I don’t actually mind the idea of single-feeding too much, I can always have a soft-point in the mag for a follow-up shot if required.

    Also not many factory loads available to try in this calibre, and those that are are bloody spendy. Have tried Fed Fusions & PowerShoks and Hornady Precision Hunters. All shot okay but nothing special.

    I might stick up a photo of a dummy round loaded to mag length next to a couple of factory rounds and see what you guys think, but it sounds like I should be okay.

  15. #15
    Member mopheadrob's Avatar
    Join Date
    Jun 2018
    Location
    Christchurch
    Posts
    695
    First photo (left to right): Fusion, Precision Hunter and LRAB at mag length.

    Name:  497890ED-B152-41A2-912A-425241A666CB.jpeg
Views: 245
Size:  1.94 MB

    Second photo: seating depth to achieve SAAMI spec.

    Name:  2E84B123-2DF3-4676-A651-BDC1E357845D.jpeg
Views: 418
Size:  2.32 MB

    I think my magazine must be around 0.025” shorter again than SAAMI; the factory PHs don’t fit.

 

 

Similar Threads

  1. 300WM Seating depth
    By Feral in forum Reloading and Ballistics
    Replies: 1
    Last Post: 01-02-2020, 02:11 PM
  2. Seating depth for Blaser
    By 25/08IMP in forum Reloading and Ballistics
    Replies: 15
    Last Post: 09-10-2015, 06:45 AM
  3. Seating depth
    By Jackangus in forum Reloading and Ballistics
    Replies: 7
    Last Post: 16-03-2015, 10:00 AM
  4. help with seating depth
    By Dino in forum Reloading and Ballistics
    Replies: 10
    Last Post: 08-09-2013, 09:12 PM
  5. seating depth changes
    By Neckshot in forum Reloading and Ballistics
    Replies: 3
    Last Post: 22-04-2013, 11:31 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!!