[silentheart]

Can you post some pictures compare the 2 rounds you have?
Side by side of rounds.
How they seat in the mag
How they contact the feeding ramp when loading?
I am interested in solving this mystery.

 

[silentheart]

OAL maybe an issue. Just my starting guess. But if they fit in the same mag, it should not be a major issue. I am actually guessing the bullet profile.
But you do have very beautiful set up. I would love to shoot one a m1 one day.

 

[silentheart]

Just a wild guess and dose not hurt suggestion.
Take the mag apart. Lube the mag spring and follower with grease. I usually use this one for clear grease.
Super Lube-21030 Synthetic Multi-Purpose Grease, 3 Oz. https://a.co/d/96zJRKE
2nd suggestion is to take a fine file and round down the front edge of mag body and also the edge of the follower. Sometime there are just rough edge and follower does not push all the way up.
Please keep us informed on the progress.
Yes, your sag is one sexy beast.

 

[silentheart]

I have a couple of steyr firearms. Love them all.
Ssg04, Aug usa a1, m9a1, m40a1 w 357 sig conversion. My price position is a GB from the military trial. Could not justify a ssg08 because it is just a ssg04 with nice chassis while ssg04 does everything I needed. Then comes the m1…
Hope the ar10 dmr will show up here in US by Christmas.

 

[silentheart]

Sorry to hear you live in NY… However, I live in the land of Lincoln, a state w most jailed politicians. Not too much better.
Yes, my ssg04 is in 308. Love it for its accuracy. I don’t reload. Just stay w 168gr good match loads. I also have a couple other bolt guns too. Tikka t3 sporter in 223, sako trg22 in 308 and a data srs a1 in 309 and 338lm. Yes, love to expend my larger cal rifle with a steyr ar10 dmr. Just completed the built of steyr m40 to 9mm barrel. Tested and works fine.
A couple of semi auto rifles like hk sl8-6/psg8 and beretta arx100.
Fun pistols like hk px4, usp in 45,40,357 and 9. P30s in 9. another pride and joy are my sp5k and sp5. Couple of cz and some beretta pistols. A couple of older Walthers. Working on a project to get a p88 sport 22lr conversion kit to work in p88 standard.
We have a couple ranges in driving distances to shoot over 200 yd. Just in general enjoy the shooting sports.
Please keep us informed on your progress.
Have a nice weekend.