Almost there with my Savage 6.5 Grendel!! One minor issue has me puzzled

[grayfox]

I finally got the PacNor barrel (an earlier thread below), sent it locally for a cerakote job, now have it mounted and headspaced. But one issue has me stumped - the magazine, rounds nose-dive rather than feeding.
The first round will feed but others nose-dive badly...
This is a Savage model 11 action (detachable mags) and I got some factory DBM mags for 7.62x39 for it, thinking that's the closest round to the 6.5 Gr.. that's when the nosediving kicks in.

Has anyone run into this, is there a solution?
Thanks.

[BjornF16]

Does this happen with all of your mags?

[bj139]

Can you see how several 7.62x39 feed from the mag? Even empty cases may provide some insight.
The major difference between the 7.62 and Grendel is less body taper in the Grendel.

The round should be fully supported by the round underneath in a double stack mag.
That shouldn't be a problem in a gun designed to feed much larger cases.

Can you post pictures of the problem?

If you have Grendel dies you may be able to size some empty brass 7.62x39 cases to a 6.5mm neck and load dummy bullets to see if these feed.

[grayfox]

Had some old pre-retirement business to attend this morning, but now am back.
To Bjorn's point I only tried 1 of the 2 I have, so I'll try the next one also.
I don't have any 7.62x39 rounds so can't address bj's suggestion. I'll also take some pix and post them.
Once upon a time I built a 6.8 spc on a savage axis, had to narrow some 243 mag lips for it to work, so I was originally thinking may need to adjust the feed lips here also... saga continues!!

[grayfox]

Answer theory #1

I looked at both mags, and the second one - initially worked ok one time, then started nose-diving on the last round.
But as I cycled the bolt it felt to me that maybe the bottom of part of the bolt head was dragging/pushing the round into the dive. Underneath, on the ptg bolt face at the bottom, was a definite streak of brass scrapings along the steel (more pronounced than I thought it should be). So I took some polish compound to it to remove the brass and smooth it out. Also I looked at the inner surfaces of the feed lips, right along the top edges, and took some polish to those as well.
Well now it does seem to feed properly for me... I tried this for both mags and I can say it has helped. I say this, however, a bit gingerly... at least I'm ready to head over to the range. Maybe this is all it is or maybe not, but I'm farther along towards a proper magazine feeding...
I'll post a pic that shows the nose dive and the bottom of the bolt head (after I smoothed it out).

nose-dive-20170712.jpg

[LRRPF52]

Looks like the feed lips have been bent in with pliers on that mag, so that there is very little contact with the case body to help position it consistently.

Getting reliably-feeding mags in a bolt gun is a problem I see all the time, especially in matches.

I've seen so many malfunctions with bolt guns in matches, I just expect it now.

Difference is it's a lot easier in most cases to correct a malfunction or stop it from getting worse since you manually feed the cartridge with bolt movement, and can often feel when something is wrong.

A buddy of mine who is an engineer and put himself through 2 different gunsmithing programs tweaks his magazines, and makes multiple feed ramps in the action even to get reliable feeding for matches.

If a company were to attempt to produce his solutions, it would take too much time and labor to make a rifle.

[grayfox]

I may have over-tweaked the one with the dive. I tried that before I noticed the scraping on the bolt head.
I'm going to try both at the range. If the one I "modified" is too far gone and unrecoverable I'll just chuck it and get another as the second mag...

[jkingrph]

I may have over-tweaked the one with the dive. I tried that before I noticed the scraping on the bolt head.
I'm going to try both at the range. If the one I "modified" is too far gone and unrecoverable I'll just chuck it and get another as the second mag...

If you think the one you modified is too far gone, try taking a sized case, or even a fired case, and fill with something that will harden good, like JBweld. put in the magazine and use a guide to form the feed lips to the case. you might have to fill the magazine with cases under that one to hold it really firmly up and lightly tap with a small hammer to help form lips down, forming them up might require removing magazine base and spring and taping that case up into the feed lips. Just an idea.

[BjornF16]

I don't recall having to modify my mags at all and have no feeding issues whatsoever.


savage grendel mag1.jpg

savage grendel mag2.jpg

If you "squeezed" the sides together you may be binding the follower at the forward end (back end rises, forward end stuck). Without any rounds loaded, do you feel any binding when you push follower down or allow it to come up? What about inserting a round and then pushing it all the way down?

[grayfox]

Back from the range. Barrel did well; I like this vortex-diamondback HP 4-12 I put on 'er. Mixed results on the nose-diving. Wish I could say everything's good but not so... Both mags did it to me.
So I single-fed for now to get thru the first break-in period for the barrel.

Back home, I did some observation on some 308 mags I have, and how the rounds move about inside the mag during the feeding. when the top ones begins to strip the next one below dives down a bit and to the left (towards the "lower ledge" of the follower) but then pops back up. So this internal dive may be more or less normal for the model 11 mag.
It could be that as an AK round for this 7.62x39 mag, the mag is expecting a fatter (.311-ish), shorter nose that can dive and recover, whereas my 123's are diving and getting stuck against the inner front. Of course then Bjorn your experience says it shouldn't be an issue at all... hmmmm
why me???
I'm going to keep playing with them, then get a couple more stock ones...
o well.

[grayfox]

Latest update... I've all but given up on my savage conversion bolt-action. I found the Howa HB action at Brownells and Bingo! it's already arrived. Off to the GS for a little customizing and I'm gtg
... already have a Boyd's stock in hand. I hope to do the break-in in about a week.

[grayfox]

R.I.P. Savage Grendel...
Turning it into a creedmoor instead.
Hello Howa mini- with Boyds stock.
Break-in and some pics to follow soon.

[s3silver]

That's too bad. What happens to the semi defective mags?

[grayfox]

They're xxx/xxx (OOOPS!!!) 7.62x39/Gr savage mags, so don't know what I'll do with them (originally I said 308 mags- my bad!! that's what I get for talking before I have my morning coffee). The grendel/savage barrel, as well... don't know what I'm going to do with that, it's on the sidelines.
2 factors weighed in on dropping the 6.5 Gr/Sav... 1) cost and uncertainty of gunsmith troubleshooting and the rifle weighed way too much for my liking for a grendel... it was going to be 11 lbs. For a 1000-yd creed I can see that, for a Gren however, not so much.
My final theory on the feeding the issue was with the ptg bolt head. PTG does say some final "gunsmithing" should be done when you get a bolt head from them, but for a 6.8 bolt gun I did, that wasn't necessary. I felt I was looking at a few hrs of gunsmith trouble shooting at ~100/hr + uncertainty, so opted to drop the project and go the CM route instead.
Put the 308 bolt head back on for the creed, so the only left-overs are the x39/grendel mags, the barrel and the grendel bolt-head.
Live and learn.

[s3silver]

Interested in selling the mags? I may take them if you give me a good deal.