Geissele Mk1 MRGG 6.5 Creedmoor initial impressions

[jmornoinf]

My initial impressions with the Geissele Mk1 MRGG 6.5 Creedmoor are all positive except for the cost. Geissele really stepped up their game with this rifle. The machining and tolerances are awesome. There is absolutely no play between the upper and lower.

The fit and finish are second to none and the recoil is noticeably lighter than my KAC 6.5 22". I believe Geissele mitigated recoil with the phased array gas block and possibley the brass weight in the BCG...not sure.

I shot both Black Hills M1200(rifle designed for this ammo or the story goes) and Berger 140 Hybrid factory loaded. I was pleasantly surprised how easy it was on the brass. My KAC gun shreds brass ~3max firings.
M1200 - 2610 ave ~ this equates to 41.2ish of H4350. On the light side
Berger 140 - 2685 ave - this same ammo does 2750 out of the KAC 22"

Groups were ok for the first outing(see pic). I estimate this gun to shoot .75" or less with hand loads(will post new groups soon). AR10 gas guns are the most challenging rifles to shoot well(I bet someone on here will disagree). I have a 6GT blot gun that I reliably shoot .250" groups consistently...It pains me to see a 1" group.

 

[putput30]

I just ordered mine. I'll report back after getting a few hundred rounds through it.

 

[JR1200W3]

My initial impressions with the Geissele Mk1 MRGG 6.5 Creedmoor are all positive except for the cost. Geissele really stepped up their game with this rifle. The machining and tolerances are awesome. There is absolutely no play between the upper and lower.

The fit and finish are second to none and the recoil is noticeably lighter than my KAC 6.5 22". I believe Geissele mitigated recoil with the phased array gas block and possibley the brass weight in the BCG...not sure.

I shot both Black Hills M1200(rifle designed for this ammo or the story goes) and Berger 140 Hybrid factory loaded. I was pleasantly surprised how easy it was on the brass. My KAC gun shreds brass ~3max firings.
M1200 - 2610 ave ~ this equates to 41.2ish of H4350. On the light side
Berger 140 - 2685 ave - this same ammo does 2750 out of the KAC 22"

Groups were ok for the first outing(see pic). I estimate this gun to shoot .75" or less with hand loads(will post new groups soon). AR10 gas guns are the most challenging rifles to shoot well(I bet someone on here will disagree). I have a 6GT blot gun that I reliably shoot .250" groups consistently...It pains me to see a 1" group.

What do the loaded rounds look like when you chamber them out of the mag and then carefully extract and eject them? Any COAL changes? Tip deformation? Scratches?

 

[matt33]

My initial impressions with the Geissele Mk1 MRGG 6.5 Creedmoor are all positive except for the cost. Geissele really stepped up their game with this rifle. The machining and tolerances are awesome. There is absolutely no play between the upper and lower.

The fit and finish are second to none and the recoil is noticeably lighter than my KAC 6.5 22". I believe Geissele mitigated recoil with the phased array gas block and possibley the brass weight in the BCG...not sure.

I shot both Black Hills M1200(rifle designed for this ammo or the story goes) and Berger 140 Hybrid factory loaded. I was pleasantly surprised how easy it was on the brass. My KAC gun shreds brass ~3max firings.
M1200 - 2610 ave ~ this equates to 41.2ish of H4350. On the light side
Berger 140 - 2685 ave - this same ammo does 2750 out of the KAC 22"

Groups were ok for the first outing(see pic). I estimate this gun to shoot .75" or less with hand loads(will post new groups soon). AR10 gas guns are the most challenging rifles to shoot well(I bet someone on here will disagree). I have a 6GT blot gun that I reliably shoot .250" groups consistently...It pains me to see a 1" group.

I think this is very promising. I'd like to get one of these rifles down the road, going to need to see a few more reports before I'm completely swayed, but I'm leaning in that direction.

I agree with you that the AR-10 large frame platform is difficult to shoot accurately for groups. I only have one ar-10, an LMT 20" 6.5 creedmoor. I was so dejected the first time I shot it. Every 5 round group was between 1.7" and 2+.

I was positive the gun or the ammunition was the problem, as I regularly shoot in the .2's - .3's with my AI AT-X and sub 1" with my more accurate AR-15 rifles.

However, after watching many videos, including some with Frank here at snipers hide, I really buckled down on shooting fundamentals, and was quickly able to shoot under 1 MOA with the same ammunition in the same rifle, same everything.

I find that mine really likes Berger 130 gr hybrids with a healthy dose of h4350. That particular bullet does really well for me especially when loaded at 2.82 or shorter to accommodate AR10 magazines.

The Berger 140 Hybrids don't do as well for me when they are loaded short, but they kick ass when I can load them longer than 2.82" COL.

 

[jmornoinf]

What do the loaded rounds look like when you chamber them out of the mag and then carefully extract and eject them? Any COAL changes? Tip deformation? Scratches?

Ejected rounds looked pretty clean…no dings and limited scratching(normal for ARs). I did not measure the change in COAL. In the past I measured change on an SP-10M and it moved .003 or so. AR10 BCG inertia is orders of magnitude more than and AR15. The hybrid bullet designs don’t seem to care. I load to max PMAG 20 length and go.

 

[JR1200W3]

Ejected rounds looked pretty clean…no dings and limited scratching(normal for ARs). I did not measure the change in COAL. In the past I measured change on an SP-10M and it moved .003 or so. AR10 BCG inertia is orders of magnitude more than and AR15. The hybrid bullet designs don’t seem to care. I load to max PMAG 20 length and go.

Most large frame ARs can't load 22,6mm, or 6.5mm VLDs or the really pointy hybrid shapes because the thin nose falls in-between the lugs and stabs the breech. I ended up getting a hold of a 22CM barrel extension for my 6.5CM SP-10. We actually went through three barrel extensions until we found one that would feed. And would feed without deforming the tip.

On your targets, you have a somewhat consistent high left flyer. Just a wild guess but I could see where an occasional near-miss of the round partially stabs the breech and slips off into the chamber, seating the bullet back causing a POI shift for that one round.

My personal theory is barrel extension feed ramp profiles are very essential to large frame accuracy due to the potential damage bullets can take during feeding. I will always be scrutinous of how these rifles feed when evaluating them. If you're going to do a review like this, it might be one of those things you test and show along with how it treats your case heads.

I've shot the BH 6.5CM contract ammo. It shoots well. Better than what your groups show. Not a dig. Just saying there's precision left on the table somewhere there

 

[jmornoinf]

Most large frame ARs can't load 22,6mm, or 6.5mm VLDs or the really pointy hybrid shapes because the thin nose falls in-between the lugs and stabs the breech. I ended up getting a hold of a 22CM barrel extension for my 6.5CM SP-10. We actually went through three barrel extensions until we found one that would feed. And would feed without deforming the tip.

On your targets, you have a somewhat consistent high left flyer. Just a wild guess but I could see where an occasional near-miss of the round partially stabs the breech and slips off into the chamber, seating the bullet back causing a POI shift for that one round.

My personal theory is barrel extension feed ramp profiles are very essential to large frame accuracy due to the potential damage bullets can take during feeding. I will always be scrutinous of how these rifles feed when evaluating them. If you're going to do a review like this, it might be one of those things you test and show along with how it treats your case heads.

I've shot the BH 6.5CM contract ammo. It shoots well. Better than what your groups show. Not a dig. Just saying there's precision left on the table somewhere there

I will take pics and measure the rounds that were chambered. The case heads are in great condition compared to my KAC rifle. I am going to get more reloads on this this rifle compared to KAC 6.5 22" and SP-10M rifles.

I believe the flyers were on me...been awhile since behind a gas gun and it was 97 degrees here in NOVA. Will post additional groups soon that include some hand loads.

see pic of feed ramps

 

[nn8734]

That particular bullet does really well for me especially when loaded at 2.82 or shorter to accommodate AR10 magazines.

The Berger 140 Hybrids don't do as well for me when they are loaded short, but they kick ass when I can load them longer than 2.82" COL.

What specific mags are you using? Are they Magpul?

I shoot 140s in my KAC 22" 6.5 and load them to 2.850". They fit and feed fine from KAC mags.

 

[putput30]

Take it for what it’s worth but Geissele supposedly says it takes about 200 rounds to break the barrel in.

 

[matt33]

What specific mags are you using? Are they Magpul?

I shoot 140s in my KAC 22" 6.5 and load them to 2.850". They fit and feed fine from KAC mags.

Yes, I use Magpul. I should probably buy some LaRue or KAC, I can only fit about 2.825" in pmags, and I don't like to go over 2.82" just to give a little cushion

That said, Berger 130s absolutely hammer for me in my LMT when loaded to about 2.780" COL (2.160" BTO). I'm happy I tried them, because they definitely give me some speed back. Getting about 2,750 FPS with a 20" barrel, and I'm below max pressure.

I like them so much that I now use them in my bolt action AI as well, I haven't shot them beyond 1,000 yet, but they are really impressive. About the same wind, slightly better accuracy and noticeably less drop than the 140 Hybrids that I was running before.

I've been experimenting with 136 gr Lapua Scenar bullets as well. Those show a lot of promise with both rifles. Just looking to standardize on one 6.5 bullet that works well with both rifles.

 

[Bigjake83]

I will take pics and measure the rounds that were chambered. The case heads are in great condition compared to my KAC rifle. I am going to get more reloads on this this rifle compared to KAC 6.5 22" and SP-10M rifles.

I believe the flyers were on me...been awhile since behind a gas gun and it was 97 degrees here in NOVA. Will post additional groups soon that include some hand loads.

see pic of feed ramps

That was the first thing I noticed, the feedramps in the Tenon is damn smart further supporting the feed geometry.

 

[JR1200W3]

KAC and Geisselle have obviously figured out the feeding of the pointy 140 Hybrids because they were both selected after testing with the contract ammo. But tolerances and variations are a thing. If I had consistent flyers like that and it wasn't always the first round or the last round, I'd be checking out how loaded but unfired bullets look.

 

[JR1200W3]

Knights MRGG submission rifles feed ramps by comparison

 

[nn8734]

Yes, I use Magpul. I should probably buy some LaRue or KAC, I can only fit about 2.825" in pmags, and I don't like to go over 2.82" just to give a little cushion

That said, Berger 130s absolutely hammer for me in my LMT when loaded to about 2.780" COL (2.160" BTO). I'm happy I tried them, because they definitely give me some speed back. Getting about 2,750 FPS with a 20" barrel, and I'm below max pressure.

I like them so much that I now use them in my bolt action AI as well, I haven't shot them beyond 1,000 yet, but they are really impressive. About the same wind, slightly better accuracy and noticeably less drop than the 140 Hybrids that I was running before.

I've been experimenting with 136 gr Lapua Scenar bullets as well. Those show a lot of promise with both rifles. Just looking to standardize on one 6.5 bullet that works well with both rifles.

Yea, I have a couple P-Mag LF gasser mags and never use them. Have several KAC mags, never had any fitment issues...I was shooting the 130s to 900m a couple weeks ago with Berger 130g OTM Hybrid factory ammo. Average MV was 2,759 over 20 rounds and SD was 20.8.

Hits were very consistent so will prob buy several hunderd of those 130Bs and develop a load w/them as well. I think 130-140g Berger bullets are the way to go w/6.5 CM gas guns..