AR15 6.5 Grendel AR10 6.5 Creedmoor Seating Depth

[TennJed]

Hi, started reloading for 6.5's Grendel and Creedmoor out of the AR 15 and 10 platform. Does anyone have any suggestions on seating depth (distance off lands)? I know we're basically limited by mag length but there still seems a fair amount of variable available on seating depth. Am I crazy or is this worth pursuing. I currently do this with bolt guns. Thank you

 

[cohunt]

In ar platforms I generally start at "max mag length" then work backwards if needed.

Different manufacturers have different internal mag dimensions ( often times ss maps have longer internal dimensions)....or start going "extreme" -- you can use a "cut out mag" to gain more room, or even start notching magwell and feed ramps to get longer.

I use "cut out mags" for my 6.8spc with 130grain bullets and I even use them in some drop box mags for bolt guns too (300wsm and 7wsm)

 

[TennJed]

Thank you, never thought of modifying the mags, great idea!

 

[cohunt]

If you like, I can send a pic--- in 12 days, I'm packing up and going elk ml hunting tomorrow-- just pm me in a little over a week to remind me and I can send a pic of my cut out mags

 

[TennJed]

If you like, I can send a pic--- in 12 days, I'm packing up and going elk ml hunting tomorrow-- just pm me in a little over a week to remind me and I can send a pic of my cut out mags

Thanks again. Best of luck on your hunt!

 

[Kmccord]

I would ask, do you have a manufactured ammo that shoots great? If so, I would copy the seating depth they are using, in my opinion, going full mag length could cause issues with not feeding properly. I did that on my 6.5 Creed in a Bergara bolt gun, the problem occurred when feeding the second shot, the tip of the bullet hung on the feeding lips of the action.

 

[TennJed]

Thanks for the experience with feeding, that's also my biggest concern. I only reload, so no factory ammo unfortunately. They both shoot very good so far, only playing at 100 yds, but both at the most 1 MOA. Started with 123 grain FMJ's from Hornady, only thing available, just got Sierra 130 TMK's so I want to really start getting serious.

 

[AllenRay]

Thanks for the experience with feeding, that's also my biggest concern. I only reload, so no factory ammo unfortunately. They both shoot very good so far, only playing at 100 yds, but both at the most 1 MOA. Started with 123 grain FMJ's from Hornady, only thing available, just got Sierra 130 TMK's so I want to really start getting serious.

I wanted to run the 129gn interlocks in my Grendel but actually had to make them 2.21"; shorter than my 123gn loads that come in at 2.24". I thought that would be a problem but they shoot as good as my longer 123 loads. The Hornady factory ammo tha t I used to shoot measures at 2.23-2.24" and I use e lander mags.

 

[338weatherby]

I'm running 99gr Hammer Hunters in my Grendel at 2.250. All of my E Lander mags need the lips opened up no matter what length I've seated to. I ran some 123 FMJ's while fire forming at 2.230 and still had issues feeding until I opened up the mag a little.

 

[TennJed]

Thank you

 

[300win mag fan]

I'm a huge fan of the Grendel in both the AR platform and a bolt gun. I agree that mag length max is a good place to start. I've had by far the best luck with ASC magazines. Both my rifle and pistol like bullets seated to mag max which for me is 2.28" Good luck.

 

[TennJed]

Excellent! I'm using ASC mags and plan on starting at max mag length and then subtracting .010 2 times for testing.

 

[Russell Sonner]

My Grendel's chamber with 123 SST's runs 2.304" so I am shooting .044" off the lands giving me a 2.260" OAL. If you are interested in a good load I get pretty good accuracy and velocity with 30.6g of LEVERevolution, 0.6" groups @ 100yds. Velocity for my 20" barrel is averaging around 2510 fps.

 

[TennJed]

My Grendel's chamber with 123 SST's runs 2.304" so I am shooting .044" off the lands giving me a 2.260" OAL. If you are interested in a good load I get pretty good accuracy and velocity with 30.6g of LEVERevolution, 0.6" groups @ 100yds. Velocity for my 20" barrel is averaging around 2510 fps.

Thank you!