Seating depth / pressure Question, .30 Carbine [Archive] - Glock Talk

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oneofthose
11-06-2011, 19:28
I cast some bullets with a lee C309-120-R with gc, sized to .308. The load data calls for 1.680 COL, but they wonít easily chamber in the olí .30 carbine at that length. I had the slap the bolt closed with my palm to get them to chamber. I fired 2 rounds that way before realizing the problem. They registered 1600 and 1608 fps, with 10.0 gr H-110 (starting load).

At 1.605 (.075 shorter) they will chamber and leave just the slightest indication of touching the rifling, but is there a potential pressure problem at this length?

Data for the 110 gr fmjís Iíve used in the past also calls for a 1.680 seating depth, which works just fine. The problem is the ogive of the cast bullet; itís fatter at the nose and touches the rifling before the bolt locks.

njl
11-07-2011, 20:25
I've been using Remington 110gr JSP, and found that 1.680" was just a little too long. I was having somewhere around 5-10% not go bang on the first try, and I think it was due to not quite being 100% in battery. I've been loading more like 1.670" or even a bit shorter and 14gr H-110 for about 1900fps.

oneofthose
11-07-2011, 22:15
I've been using Remington 110gr JSP, and found that 1.680" was just a little too long. I was having somewhere around 5-10% not go bang on the first try, and I think it was due to not quite being 100% in battery. I've been loading more like 1.670" or even a bit shorter and 14gr H-110 for about 1900fps.

Before I started casting, my pet load was a 110 gr remington fmj with 12.5 gr H-110 at 1.680. My best 10 shot group with that load was 1.7" at 50 yards. Don't know if I'll ever get there casting my own bullets, but I'll try. The 30 carbine is not known as a particularly accurate rifle, but this old Inland is the most accurate I've had.

njl
11-07-2011, 22:43
I've got some OLD Norma 30 carbine ammo that's JSP, that measures 1.666" and some GA Arms 110gr JSP that's only 1.635" and does a very consistent 2035fps. The Norma was just under 2000fps. I'd be more worried about leading and clogging the gas port than pressure...though if leading is an issue, won't that raise pressure?

oneofthose
11-08-2011, 12:35
I've got some OLD Norma 30 carbine ammo that's JSP, that measures 1.666" and some GA Arms 110gr JSP that's only 1.635" and does a very consistent 2035fps. The Norma was just under 2000fps. I'd be more worried about leading and clogging the gas port than pressure...though if leading is an issue, won't that raise pressure?

I seated the remaining rounds down to 1.605 and fired them yesterday. Averaged 1503 fps with 10.0 gr H110, 1552 w/ 10.5 gr, 1580 with 11.0 gr. No signs of leading, I was actually surprised how easily it cleaned.

I've heard warnings about lead with a gas operated system, but a few people have reported zero issues with .30 carbine, so I decided to give it a try. I'll see how things go.