Printable View
Hey guys
Recently worked out seating depth for loading projectile 10thou of from the lands in my Sako A7 7mm-08.
As you can see in the photos, the ballistic tip is going to prevent loading any more than one round.
Does anybody have any experience modifying the mag to accept the new bullet seating depth?
Looks to me like a job for the die grinder but if there is a tidier way id like to know it!
Cheers
You don't have much room to work with, so at the most you could carve out 2-3mm from the front of the mag.
This seems to be a major annoying issue with the A7, as I'm loading 300WM for an A7.
In that, the 180gn factory ammo touches the front of the mag already. :yuush:
That second photo wasn't a good representation (poor angle)
Have replaced with straight up n down shot.
Take it to an engineering shop and get them to mill it out.
A 6mm cutter plunged in would do it easy.
Will be far more tidy than grinding it out.
Have you checked your rifles accuracy with your projectiles seated deeper to fit in the mag
Plenty of rifles have stunning accuracy with projectiles jumping 100thou plus to the rifling lands.
Do you know 0.010" jump will work? A mate hade the exact same rifle and it was very accurate with mag sized seating length.
Have acheived 0.87 of an inch at 100yards with stock seating depth.
Striving for better.
Will it eject a loaded round at that length?
seat it deeper, job done.
or do it properly and get it neatly milled, its a no brainer really
I dunno @heisenberg and this is a comment making a heap of assumptions for the 7mm08. But is there a reason why the projectile looks a long way out? Have you got or are dealing with a compressed load to put it at this particular seating depth.
If not my advice and I took the same having the limitation of a 162 Amax going into a 7mm rem mag she'll was to get it to a seating depth that just fitted inside the magazine. From there I loaded a ladder starting at mid value on the reloading tables to find a load that enabled me to have a non compressed load but also get the accuracy I was after. For me it was found in my tikka at 63gr of IMR 7828 which got me a 2895 speed value.
A couple of weeks ago I bought a set of digital calipers and realised the load I'd used for a while now 20 odd rounds was at (including balistic tip) 3.330" instead of the max oal of 3.290" whoops, so just trying to work out if I need to redo the load again at the desired length staying under the recommended Sami oal.
It shot .42 (to the centres) which I'm really happy with - but my point to you is can you dial things back a bit to get your desired accuracy you don't need to get caught up in the speed races that some do or too caught up on a particular jump or seating depth just work with your limitations - if they are limitations. Change powder if the cartridge is too full to seat inside the magazine is another suggestion.
Lastly as I was thinking i was going to have to do on the tikka t3 was to replace the stock and bottom metal to allow a magazine that would do this or single load potentially...
I've dialled back and that's worked very nicely for me!
My 2c from another perspective...
Yep what he said, i done some loads for an A7 7mmrm and it had a 240 thou jump roughly and i considered what you are proposing cos it was only 1.4mm to grind out and i had 4.4mm to use.Quote:
Originally Posted by 7mmsaum
End of the day i tried loading to the mag and loaded the powder in .5 increments until i found a load that worked(.713") with no pressure signs.
Good point right there, cos a 7mm rem mag wont!Quote:
Originally Posted by veitnamcam
Whats your issue with compressed loads?Quote:
Originally Posted by Carpe Diem
Yeah great point there VietnamCam and no it catches, just.
Here is a photo to compare it to standard overall length.
Don't have a issue at all, a personal preference possibly?... One of my previous compressed loads wasn't that consistent in another cal - but hey that could have been anything.... But as you and I know confidence is everything in what sometimes can be a completed mind fuck around getting comfortable with a load.
So should i try a group at 10thou off the lands or seat the bullet just inside the magazine?
Would prob be 20-30thou off the lands then and at least then it would be guaranteed to fit and eject if needed.
If a dedicated gong/long range round then single feeding is fine, otherwise mag fit and make it shoot.
For what its worth. I am 110 thou off lands in 7mm saum and 20 thou in 708 to fit mag using accubonds. Both rifles will do .5 groups with not much problem. I concentrate more on case prep and load consistency ;)
Easy as to make the tikka t3 mag longer 2.890" OAL in 7mm08 consistent half inch groups would post photos if i had another mag to modify
10thou of the lands on my Sako makes the OAL 2.930
So, only my 2c$.
I did reload for my Tikka Lite 7-08 and it shot nicely with mag length. In the other hand, my 7mm Rem Mag shoot well with two different projectiles(amax's and sst's) any day with magazine length but not good at all as soon I start to play with the seating depth.
Try the options you have from the previous suggestions, and go from there, I personaly think you still can get a lot of accuracy without hassle.
All the best, good luck!
Mac
7mm Rem Mag with 162gr Amax at 3.300" just fitting the mag...
Attachment 33851
7mm Rem Mag with 162gr SSTs at 3.300" as well and same powder load for both.
Attachment 33852
All 4 shots group!
Have done another 3 loads at 30thou from the lands and they fit the mag and feed fine.
Will group tomorrow and post results.
I load both my .223 and .270 Sako 75s and a mates A7 to fit the mag (and to be able to extract an unfired round), and still shoot 0.5 MOA, best groupings of 0.27 and 0.28 MOA.
If you have concentric rounds, consistent neck tension and with minimal runout, then seating the projectiles with a jump to fit the mag (some projectiles can handle a jump more than others), the seating depth isn't quite so crucial.
Luckily the T3 in 6.5x55 can be seated to touch the rifling and easily still fit in the mag.
