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6mm Ar question

4dds

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Minuteman
Dec 15, 2017
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Before I spend hours going down the rabbit hole I figured I’d just ask. Will any of the 6mm offerings in an ar15 platform allow me to push a 95VLD to 2900 out of an 18” barrel? I’m looking for a lighter hunting setup to use when I don’t want to lug my 15lb 6.5 out.
 
Before I spend hours going down the rabbit hole I figured I’d just ask. Will any of the 6mm offerings in an ar15 platform allow me to push a 95VLD to 2900 out of an 18” barrel? I’m looking for a lighter hunting setup to use when I don’t want to lug my 15lb 6.5 out.
After checking the Hodgdon Reloading Data Center it looks like you should be able to
 
I've got a 16 inch 6mm arc Proof Barrel in my KAC SR-15, hands down best overall rifle I have for anything under 1200 yards. Stupid accurate.
 
I have a 24" Criterion 6ARC from Compass Lake pushing 105VLDs at 2626 with a very mild H4895 load of 26gr. I have some 95s also but have not messed with them yet. I'm pretty sure that with LVR or CFE you could get 2900 in a fast 18" from the 95s.
 
I was wondering how the 6arc was doing. I have had phenomenal success with a Berger 95VLD on deer out of my 243 and would like to get a smaller overall package. And if I can do it in an AR that would be awesome.
 
The factory Hornady ammo is expensive and rare, but hands down it is now my go to gun for all things hunting until I need to step up to my 300 PRC. That being said it is my gassiest gun suppressed even with an adjustable gas block. Still stupid accurate and exceptional performance.
 
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You can't push an 88 ELDM at 2900 using CFE out of a 22" 22Grendel so I doubt you can from a 6 grendel with 4 less inches of barrel.
Well... You can, but it is a really hot load, and you'll probably be seeing pierced primers...
 
You can milk anything with nipples.

2850 in my 22 Grendel makes 3 shot brass and the caseheads almost don't fit in a shellholder.
wouldn't being less overbore actually help this? similar to a 30SM pushing 215s at the same speed as 195 from a 28SM? substitute 7/300NM and 300NM
 
Not that much, to gain 100fps? With a 4" shorter barrel to boot?

All this 6mm AR stuff has been figured out. I remember reading Whitley's stuff back in 2008. I went round and round wanting to build a 6mm AR. After going through everything published, the idea of getting a reliable 2900fps out of a 6mm Grendel based cartridge just wasn't feasible without using single load, 26" high-power setups. My experience with the 22 Grendel supports this. Now we reduce the case capacity of a 6mm Grendel in the 6ARC and it sells like hotcakes. I don't get it.
hornady marketing at it's finest
 
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You can milk anything with nipples.

2850 in my 22 Grendel makes 3 shot brass and the caseheads almost don't fit in a shellholder.
The brass looked fine out of mine with 88gr ELD-M bullets at 2850 fps (no signs of over-pressure), though I moved down to 2750 so that all of the bullets would impact the target BEFORE they exploded. I pierced a primer at 3050 🤫
 
I am not a reloader and it's not worth my time. Some of my buddies did testing for the 6mm ARC in the DoD and wouldn't shut up about it. So I picked up a proof barrel and I find it superior to the MK262 Mod 1 I was pumping through my SR-15 at the time. It was dead on at 600 with my DOPE and I have no need for anything past that. So for me, it was a no brainer when I picked up multiple cases of the ammo when it was just coming to the market.
 
I’m getting 2950 out of a 22” tube with LVR and 90 grain TGK’s with my 6 Grendel and probably could go up in load charge as there are no brass issues. I think your limiting factor is going to be an 18” barrel.
 
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Not that much, to gain 100fps? With a 4" shorter barrel to boot?

All this 6mm AR stuff has been figured out. I remember reading Whitley's stuff back in 2008. I went round and round wanting to build a 6mm AR. After going through everything published, the idea of getting a reliable 2900fps out of a 6mm Grendel based cartridge just wasn't feasible without using single load, 26" high-power setups. My experience with the 22 Grendel supports this. Now we reduce the case capacity of a 6mm Grendel in the 6ARC and it sells like hotcakes. I don't get it.
Pretty much. Same with 100g in the 6.5 Grendal. Anyone driving those 2900 out of an 18"? 🤣🤣 Mine shoots them great, at about 2550.

Lets see what Hodgdon says, 2730 out of a 24" for the 6.5g with 100g.

6ARC they got the 95TMK to 2830 with BLc-2, and a 24" barrel. So its probably max looking at 2730 through an 18" ar-15. Probably more like 2680 if your AR-15 can make it to the book max load. I wouldn't be expecting more than about 2600.
 
Pretty much. Same with 100g in the 6.5 Grendal. Anyone driving those 2900 out of an 18"? 🤣🤣 Mine shoots them great, at about 2550.

Lets see what Hodgdon says, 2730 out of a 24" for the 6.5g with 100g.

6ARC they got the 95TMK to 2830 with BLc-2, and a 24" barrel. So its probably max looking at 2730 through an 18" ar-15. Probably more like 2680 if your AR-15 can make it to the book max load. I wouldn't be expecting more than about 2600.
And, sometimes the hodgedon data just doesn't match reality. They report 2497 FPS from a 24" barrel using a 123gr Sierra HPBT and 8208XBR powder. 5 shot from my 22" JP AR15 barrel averaged 2604 FPS and I'm getting 2535 (avg) from 27.7gr.
 
And, sometimes the hodgedon data just doesn't match reality. They report 2497 FPS from a 24" barrel using a 123gr Sierra HPBT and 8208XBR powder. 5 shot from my 22" JP AR15 barrel averaged 2604 FPS and I'm getting 2535 (avg) from 27.7gr.

What makes you think your 27.7 load is not 50k psi like their top load that went 2497?
 
I have a 6mm predator, that is identical to the 6mm at and 6mm grendel, so a very slight step up from the 6arc.

My current load is doing 2850 out of a 22in barrel with a 90gr game changer with benchmark. 8208xbr is pretty much identical. Lapua and norma brass only last 3-4 firings and it is a little too hot so my next round will have to slow down. I could only find starline to neck down so I'm gonna have to redo load dev anyway. Probably better off down about 2650 or so.

You could hot rod it with leverevolution or some of the ball powders probably, but I wouldn't expect anything to last very long.
 
I have a 6mm predator, that is identical to the 6mm at and 6mm grendel, so a very slight step up from the 6arc.

My current load is doing 2850 out of a 22in barrel with a 90gr game changer with benchmark. 8208xbr is pretty much identical. Lapua and norma brass only last 3-4 firings and it is a little too hot so my next round will have to slow down. I could only find starline to neck down so I'm gonna have to redo load dev anyway. Probably better off down about 2650 or so.

You could hot rod it with leverevolution or some of the ball powders probably, but I wouldn't expect anything to last very long.
Your pressures with Benchmark or 8208 are at least as hot as the “hot rodded” Lever loads you refer to.

SMH at the lack of basic understanding of burn rates and powder densities with some of the posts here. Old load data from Whitley, or someone’s 8208 or 4895 loads, etc, do not reflect what these cartridges are capable of with Lever. It doesn’t take much experimentation to see the evidence if you have a good idea what you’re looking at.

Anyway- OP, 2900 in an 18” would be a fairly hot load, but you can get pretty close with Lever. You’ll probably be more comfortable around 2,850 or so.
 
I had an 18” 6.5G and ended up selling it. I just couldn’t get a bullet to preform the way I wanted on deer. And I believe it was due to lack of speed. Looking back at my notes it looks like I had 95gr V-max up to 2850ish but couldn’t get any accuracy. And also had the 130 vld up to 2600 but it just wouldn’t preform on game.
 
I had an 18” 6.5G and ended up selling it. I just couldn’t get a bullet to preform the way I wanted on deer. And I believe it was due to lack of speed. Looking back at my notes it looks like I had 95gr V-max up to 2850ish but couldn’t get any accuracy. And also had the 130 vld up to 2600 but it just wouldn’t preform on game.
Should’ve tried the 129gr ABLR. Excellent bullet for the Grendel, even from short barrels because it performs well at low velocity.