6.5 grendel 180?
- Thread starter Bman12456
- Start date
You need the x39 bolt, a barrel and Grendel mags. Probably a longer op-rod, i don't think a carbine Grendel barrel exists. From there it should be fairly straight forward. The only gotcha i have found with using AR barrels on the MCR was the gas hole needed to be opened up a bit. At which point an adjustable gas block is handy in case you go too far or need to tune for your load.
Looks like only the Type 1 6.5 Grendel uses a 7.62x39 bolt as the Type 2 bolt face depth is 0.136" where the Type 1 is 0.125"
Id either need to find a Type 1 18.6+" barrel (unobtainium), have one made, or see about having a custom 180 bolt machined for 6.5 grendel.
Id either need to find a Type 1 18.6+" barrel (unobtainium), have one made, or see about having a custom 180 bolt machined for 6.5 grendel.
I'd talk to IBI about a barrel. Last I chatted with them they use a Type 1 Grendel reamer. I've been pondering a similar project to yours but kinda waiting for a 180 with a more sealed up upper to become available as I'd also like to hunt with it in ####ty coastal weather.
If you don't mind brick-like ergonomics, and would rather use a gas tube and a standard AR adjustable gas block with a Type 1 Grendel barrel, you may want to contact Sylvestre and confirm when they will be bringing in .441 Rim Diameter bolt face build kits for the Jard J180. They haven't brought in the larger circumference kits yet, but the .556 kits have been performing well when properly lubricated. The gas tube impinges a Stoner-style pseudo piston BCG and bolt against receiver internal AR180-style dual recoill springs along dual guide rods. The kit also comes with the other receiver internals, including a decent Jard trigger, and basic pistol grip, so you just need a non A2 style (or A2 with carbine adapter) stock, standard AR forend components, magazine, and optic to make a whole firearm.
Regardless of the WK, MCR, or J180 host, forum vendors IBI and ATRS should be able to make a Grendel Type 1 barrel to order. I know RWA made at least one Grendel in the RWA180B before discontinuing production, using an IBI barrel, as posted here -> https://www.canadiangunnutz.com/forum/showthread.php/1846468-WK-180-gas-blow-by-from-gas-port-area?p=15789087&viewfull=1#post15789087
Regardless of the WK, MCR, or J180 host, forum vendors IBI and ATRS should be able to make a Grendel Type 1 barrel to order. I know RWA made at least one Grendel in the RWA180B before discontinuing production, using an IBI barrel, as posted here -> https://www.canadiangunnutz.com/forum/showthread.php/1846468-WK-180-gas-blow-by-from-gas-port-area?p=15789087&viewfull=1#post15789087
Have you seen the RS18? They're making it with a non-reciprocating charging handle and charging handle track cover. They intend to have an ejection port cover next year for their LE edition, but the initial version will have the BCG seal the charging port quite well when forward. The J180 isn't as pretty, but you can purchase a charging slot dust cover for it, and it too has a nicely closed action with the bolt forward, almost like the BRN-180.
Yeah IBI seems like the best option for having one made. I have the TNA enhanced upper and lower on my shorty 11.5 and its fairly sealed with the right side dust cover. I plan on figuring out a Sig 55x style rubber slit dust cover for it eventually if the open charging handle track proves to be an issue. I plan to beat the ever loving dog sh*t out of the 11.5 just to see how it holds up.
Ive heard good things about the Jard but I cant get over how toaster-esque it looks. Im probably going to go with a Lynx 180B lower and possibly the Spectre upper if it comes out any time soon.
Yeah, I'm keeping an eye on the RS18. It looks like the way forward to me but waiting for a few to be out in the wild being as it's not inexpensive.
I'd love to see a Sig 55X style rubber slit dust cover for the charging handle track on the MCR. I'm not stressed about the ejection port as the BCG closes things up pretty good. The charging handle slot is massive though and goes right back over the trigger. Looks way to easy to get #### in the trigger mech for me to want to take it out in real ####ty weather.
... and tna just released a 6.5 grrrendel bolt for $200. appears to be 7.62x39 0.125" bolt with the face recessed an additional 0.01" to 0.136" or so. ibi will do a 19" or 20" grendel barrel at the twist of your choice either mid- or rifle-length with 0.125" or 0.136" headspace for $440. tna also sells a rifle length gas system for $200 (no mid-length aftermarket options that i am aware of) so you should be able to convert your 180 to grendel for around $850, or less if you have 7.62x39 and are good with the 0.125" bolt.
Im going to have to pick me up one of those bolts ASAP. I wont be doing a conversion, but rather a full build from the ground up as Im doing with my shorty. Stoked they dropped a Grendel bolt, way more barrel options for the Type 2 bolt ��
the tna upper looks to be the best of what's currently available. they could provide the upper/lower with bolt carrier at $865, the rifle-length gas system at $200, the bolt at $200, and a barrel from ibi at $440; say $1700 plus trigger, furniture, and small parts. well over $2k all said and done. sure does add up. and if you're like me, it's to replace a 308 that got banned. doubt the buy-back will cover it!
for me, the question is the durability of a rifle-length gas system on a 180 clone, as well as the impact on accuracy.
If you're not in a rush, you may want to wait on the SBI direct impingement bolt control group for their 180 upper and the WK/MCR. You could then forgo the piston entirely, and use a standard AR adjustable gas block with a gas tube, while having your choice of the various WK ergonomic lowers.
If you're gonna get a barrel from IBI, you might as well just get the 7.62x39 bolt as they have a Type 1 reamer for Grendel. I say this because it appears that TNA's Grendel bolt is just a x39 bolt with the recess cut a bit deeper and then no surface treatment applied (ie bare metal). The only reason I'd get their Type 2 bolt would be to get a standard AR-type Grendel barrel but there don't seem to be many available in country now. Would be nice of TNA would surface treat these new bolts...
so, currently drinking a saturday morning coffee and seriously avoiding chores. i thought i would take a few minutes to share what i've glreaned from the interweb regarding the whole grrrrendel bolt face debate. ps, i'm no expert and what i write here is worth what you paid for it, so caveat emptor.
much like 300blk is an excercise in getting the 22 cal 556 case to shoot a 30 cal bullet out of an ar 15, the 6.5g is an effort to get a 7.62mm x39 case to shout a 6.5mm bullet out of an ar 15. as such, the 6.5g is fundamentally a necked-down 7.62x39 (generally; in actuality i think the 6.5g and the 7.62x39 have the same parent case - a slight difference). regardless, a 7.62x39 case can be resized to shoot 6.5g and the case rims are the same dimensions.
out in the world right now, a 5.56 ar 15 bolt has a face recessed 0.125". a 7.62x39 ar 15 bolt has a face recessed 0.125". a 6.5g ar 15 bolt can have a face recessed either 0.125" or 0.136". the distance from the bolt face when the lugs have locked into the barrel extension to the shoulder of the case where it sits in the chamber reamed into the barrel is called the headspace. so, don't go too deep with the reamer and the end of the case hangs out 0.136"; go a little deeper and it only hangs out 0.125". it all can be measured/confirmed with go/no go gauges. otherwise, to much headspace and the case can slam against the bolt and shear lugs off. too little headspace and the bolt won't close.
so, the question is, why two different bolt types for 6.5g, and which one is better? lots of noise on the interweb, and from what i can discern there are four theories, and the reality is probably some combo of all 4 ...
1) 6.5g was developed by alexander arms, who tried to patent the idea. part of the patent included the 0.136" headspace requirements - to deter competition, and to ensure they could augment profits with bolt sales. note that the patent and success of 6.5g created a lot of effort by other vendors to circumvent the patent; les baur customs created an exact copy called the 0.264 LBC, there is also the interchangeable '6.5 sporter'. part of these efforts is the change to a 0.125" bolt face recess, which also allowed use of a 7.62x39 bolt instead of a specific 6.5g bolt. note that there is some nomenclature out there there where type i grendel signifies a 0.125" bolt face recess, while type ii is 0.136", however ever since alexander arms got the 6.5g saami approved they have removed the patent and the industry seems to be standardizing at 0.136" and just calling it 'grendel'.
2) when 7.62x39 first came to the ar 15 platform it used a 0.136" bolt face recess, but later standardized to 0.125" to facilitate bolt production. when alexander arms developed the 6.5g from the 7.62x39 ar 15, 0.136" was still in use.
3) the wider diameter rim of the 7.62x39 case required removal of more material from the bolt face and less support for the lugs. the added pressure behind the 6.5g was causing lugs to shear off. how real is this? dunno; i do know that one pic hits the internet and everyone looses their mind.
4) with the shallower 0.125" bolt face recess the extractor engagement of the rim wasn't 100% and this sub-par operation was causing extractor failures. again, could be interweb hysteria, however alexander arms did envision the 6.5g as a complete 556 replacement and did intend it to run with cheap steel ammo. note that part of re-sizing the 7.62x39 case to 6.5g involves removing the taper from the case and straight-walled cases (especially steel) can be more difficult to extract, so some of the extractor issue may be due to steel case ammo.
there you go. which bolt? depends i think on how you are going to use the gun. hunting gun running high quality brass and not loaded too too hot? 7.62x39 bolt should be find. 16" ammo burner 5.56 3-gun replacement with cheap steel ammo or super-hot 1000 yard loads? perhaps consider a 0.136" grendel bolt.
much like 300blk is an excercise in getting the 22 cal 556 case to shoot a 30 cal bullet out of an ar 15, the 6.5g is an effort to get a 7.62mm x39 case to shout a 6.5mm bullet out of an ar 15. as such, the 6.5g is fundamentally a necked-down 7.62x39 (generally; in actuality i think the 6.5g and the 7.62x39 have the same parent case - a slight difference). regardless, a 7.62x39 case can be resized to shoot 6.5g and the case rims are the same dimensions.
out in the world right now, a 5.56 ar 15 bolt has a face recessed 0.125". a 7.62x39 ar 15 bolt has a face recessed 0.125". a 6.5g ar 15 bolt can have a face recessed either 0.125" or 0.136". the distance from the bolt face when the lugs have locked into the barrel extension to the shoulder of the case where it sits in the chamber reamed into the barrel is called the headspace. so, don't go too deep with the reamer and the end of the case hangs out 0.136"; go a little deeper and it only hangs out 0.125". it all can be measured/confirmed with go/no go gauges. otherwise, to much headspace and the case can slam against the bolt and shear lugs off. too little headspace and the bolt won't close.
so, the question is, why two different bolt types for 6.5g, and which one is better? lots of noise on the interweb, and from what i can discern there are four theories, and the reality is probably some combo of all 4 ...
1) 6.5g was developed by alexander arms, who tried to patent the idea. part of the patent included the 0.136" headspace requirements - to deter competition, and to ensure they could augment profits with bolt sales. note that the patent and success of 6.5g created a lot of effort by other vendors to circumvent the patent; les baur customs created an exact copy called the 0.264 LBC, there is also the interchangeable '6.5 sporter'. part of these efforts is the change to a 0.125" bolt face recess, which also allowed use of a 7.62x39 bolt instead of a specific 6.5g bolt. note that there is some nomenclature out there there where type i grendel signifies a 0.125" bolt face recess, while type ii is 0.136", however ever since alexander arms got the 6.5g saami approved they have removed the patent and the industry seems to be standardizing at 0.136" and just calling it 'grendel'.
2) when 7.62x39 first came to the ar 15 platform it used a 0.136" bolt face recess, but later standardized to 0.125" to facilitate bolt production. when alexander arms developed the 6.5g from the 7.62x39 ar 15, 0.136" was still in use.
3) the wider diameter rim of the 7.62x39 case required removal of more material from the bolt face and less support for the lugs. the added pressure behind the 6.5g was causing lugs to shear off. how real is this? dunno; i do know that one pic hits the internet and everyone looses their mind.
4) with the shallower 0.125" bolt face recess the extractor engagement of the rim wasn't 100% and this sub-par operation was causing extractor failures. again, could be interweb hysteria, however alexander arms did envision the 6.5g as a complete 556 replacement and did intend it to run with cheap steel ammo. note that part of re-sizing the 7.62x39 case to 6.5g involves removing the taper from the case and straight-walled cases (especially steel) can be more difficult to extract, so some of the extractor issue may be due to steel case ammo.
there you go. which bolt? depends i think on how you are going to use the gun. hunting gun running high quality brass and not loaded too too hot? 7.62x39 bolt should be find. 16" ammo burner 5.56 3-gun replacement with cheap steel ammo or super-hot 1000 yard loads? perhaps consider a 0.136" grendel bolt.
yes. not a lot of piston guns in grendel, and not a lot of rifle-length piston guns. end result, next to no rifle-length piston guns in grendel, so this is a bit of an experiment. waiting for more di 180 clones might be the answer.
DI (ish, Stoner piston is technically no true DI) could work out well. When properly lubed, the .223 Jards made so far seem to have functioned well. Hopefully a Grendel J180 will work as well, and will also provide proof of concept for a svelter SBI DI Lynx Grendel for those who can't put up with the Jard's lack of ergonomics and aesthetics on the pistol grip area (though it does have a nice straight magwell like the TNA lower).
