GAP-10 .308 shooters: What's your seating depth for magazine loaded rounds?

[SWThomas]

I'm still in the process of working up loads for my GAP-10 chambered in .308WIN. Right now I'm focusing on the 175 SMKs with IMR 4064. I'm currently seating them to where the tips are almost touching the magazine when loaded. I figured I would work my OCW with this length and then seat them a little deeper once I find the right charge.

I'm just trying to get an idea of the seating depth you guys use for either 175s or 168s. And do you measure from the tip to rim or from ojive to rim?

 

[dlouie87]

Hello Thomas,

I don't have a GAP-10 but for my JP, I trim to 2.005 (+/- .002) and I have a COAL of 2.800 (+/-.003) with the 168smk. I don't trim the meplat so that could be where my variances is coming from. I don't remember the COAL from ogive measurement but I can get that for you if you need it.

 

[SWThomas]

Hello Thomas,

I don't have a GAP-10 but for my JP, I trim to 2.005 (+/- .002) and I have a COAL of 2.800 (+/-.003) with the 168smk. I don't trim the meplat so that could be where my variances is coming from. I don't remember the COAL from ogive measurement but I can get that for you if you need it.

Nah, no need. I was just trying to see where everyone measures from. It seems that measuring from the ojive would give more accurate readings. 2.800 seems to be a pretty common OAL. Are you getting good results with that seating depth? Have you lengthened or shortened it to see the difference on target?

 

[Ultraman550]

I know this might sound like blasphemy but I dremel off the tip on my SMK's with a very fine grit. It seriously takes about a millisecond and its very easy to see how much needs to come off without grinding too far down and exposing the inner material. You can obviously buy a metplat trimmer which is less barbaric than what I do but I have not had any problems at all. I also measure from the ogive because like you said, its more accurate.

 

[FLIGHT762]

I have a GAP 10 delivered last August. I've loaded 155 Noslers, 168 Noslers, 168 Hornady AMAX, 175 Noslers and 178 AMAX's for it. Nearly all of the bullets are loaded between 2.770"-2.785". I get a lot of 5 shot groups between .40"-.75".

This rifle shoots well. I don't have to mess much with trying to tweak the COL. I want the rifle to reliably function within magazine length, so all COL lengths will be @ or under 2.800".

 

[sic65stang]

My Gap 10 is 18.5". My load for that combo is 42.5 4064 (actually tested this, not just taken from MK316 Mod 0) and I load at OAL 2.805.

 

[dlouie87]

I have not messed with the seating depth. I'm still new to all of this reloading stuff so, I'm learning as I go. I think I'm going to try +/- .010 of the seating depth.

So I'm going to try 2.790 and 2.810 next. I think that is the way to do it but I need to double check with the OCW website. My load out of an 18'' JP is LC match brass, 42 gr of varget, 168smk , and COAL 2.800.

 

[Shoottothrill]

I have a GAP 10 delivered last August. I've loaded 155 Noslers, 168 Noslers, 168 Hornady AMAX, 175 Noslers and 178 AMAX's for it. Nearly all of the bullets are loaded between 2.770"-2.785". I get a lot of 5 shot groups between .40"-.75".

This rifle shoots well. I don't have to mess much with trying to tweak the COL. I want the rifle to reliably function within magazine length, so all COL lengths will be @ or under 2.800".

Whats your barrel length and what kind of velocity with the 178 AMAX? Thanks

 

[FLIGHT762]

Whats your barrel length and what kind of velocity with the 178 AMAX? Thanks

22" barrel. I didn't run the 178's across my Magnetospeed, I only had 10 bullets left out of a box I had used for testing in other rifles. I used 40.0 of AR COMP in a Hornady case with a Tula primer. I have shot that same load with the 175 Nosler's and I was getting an AVG of 2598 FPS. I would guess I'm getting very close to that with the 178's.