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6.5 Grendal Barrel Length Suggestions?

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SKYNET KC

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Minuteman
Feb 6, 2013
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Looking to build a 6.5 Grendal to punch some paper out to about 800 yards with. This will be my first precision semi-auto build so I figured I would try and tackle the barrel first since it's going to take a while to order or have made.

I'm thinking 20" on the barrel length with a 1/8 twist. Suggestions from anyone else before I start searching? I'm not really up to date on good barrels for semi's, so any suggestions from you guys would be fantastic!

Thanks,
Matt
 
I ran an 18 inch with a 1-8 twist for a long time. If I was to do it again and wanted to get the most out of the cartridge I would go 22.
 
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mjh30 said:
I ran an 18 inch with a 1-8 twist for a long time. If I was to do it again and wanted to get the most out of the cartridge I would go 22.
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Why do you say that? I'm not doubting you, just wanting to hear your personal reasoning behind it. Were you hand loading?

Also, I can't find a muzzle brake to save my life for 6.5. Any ideas?
 
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Precision Armament makes an excellent Brake for a 6.5. I run one on my Beanland 260, and recoil is like a 243 with a good brake. I have several for a 6.8 that will work great on a 6.5 as well.
 
Skynet, for a brake I was using something simple, it was a Black River tactical linear brake in 6.5 threaded 5/8-24, inexpensive but effective. With regards to barrel length, I ran the 18 with a 1/8 twist, was it optimum no not really it was a compromise, if that last statement makes sense. I wanted to shoot the heavies, 123's instead of lighter bullets, I wanted higher bc's. You want to build a precision ar to shoot paper at 800 yards maybe more. What about a 24 inch barrel with 1:8 twist, with an extended gas system shooting 130's around 2750, now we are talking. Now is 24 inches as portable as 18, no, but what do we want here.
 
mjh30 said:
Skynet, for a brake I was using something simple, it was a Black River tactical linear brake in 6.5 threaded 5/8-24, inexpensive but effective. With regards to barrel length, I ran the 18 with a 1/8 twist, was it optimum no not really it was a compromise, if that last statement makes sense. I wanted to shoot the heavies, 123's instead of lighter bullets, I wanted higher bc's. You want to build a precision ar to shoot paper at 800 yards maybe more. What about a 24 inch barrel with 1:8 twist, with an extended gas system shooting 130's around 2750, now we are talking. Now is 24 inches as portable as 18, no, but what do we want here.
Click to expand...


We're Honey Badgers, we don't give a shit.

Great posts guys. Thank you so much. I'll make a thread for the build here soon when I start getting parts ordered. :)
 
I have tried 14.5, 16, 18, and 22.5. The Satern 22.5 is my precision long-range barrel setup and the 14.5 is my do-it-all truck gun.
If I could only have only one it would be at least 20". There are lots of muzzle devices available---Surefire makes some great ones or VIAS etc. anything marked 6.8 works great! VLTOR makes a regular flash hider for 6.5 Grendel.
 
Good luck running 2750 I get 2650 out of my 24" bhw with handloads. If do a 20"if I did it agsin

mjh30 said:
Skynet, for a brake I was using something simple, it was a Black River tactical linear brake in 6.5 threaded 5/8-24, inexpensive but effective. With regards to barrel length, I ran the 18 with a 1/8 twist, was it optimum no not really it was a compromise, if that last statement makes sense. I wanted to shoot the heavies, 123's instead of lighter bullets, I wanted higher bc's. You want to build a precision ar to shoot paper at 800 yards maybe more. What about a 24 inch barrel with 1:8 twist, with an extended gas system shooting 130's around 2750, now we are talking. Now is 24 inches as portable as 18, no, but what do we want here.
Click to expand...
 
Precision308, did you read my post. I actually ran one of Carls early barrels for a long time, 18 inch rifle length gas system with 1/8 twist, type 1 bolt so I always had to keep a spare lying around, accurate as hell, even though BHW rep hasn't been the greatest, I will vouch for the accuracy of their barrels though. With regards to 2750 out of a 24 inch barrel, I am talking about a upper with an extended gas system. I personally think the gas system length, combined with barrel length is really the answer for getting the most out of the Grendel, plus a few newer powders available can help speed this along and these folks are shooting 130 grain bullets.
 
mjh30 said:
Precision308, did you read my post. I actually ran one of Carls early barrels for a long time, 18 inch rifle length gas system with 1/8 twist, type 1 bolt so I always had to keep a spare lying around, accurate as hell, even though BHW rep hasn't been the greatest, I will vouch for the accuracy of their barrels though. With regards to 2750 out of a 24 inch barrel, I am talking about a upper with an extended gas system. I personally think the gas system length, combined with barrel length is really the answer for getting the most out of the Grendel, plus a few newer powders available can help speed this along and these folks are shooting 130 grain bullets.
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I was just speaking from my experience. I have two 24" barrels both have rifle length gas and neither will hit 2700 with 123. I'm sure there are ways around it but I'm speaking of my experience and what most others have experienced feom my area. What powder were you runing your 130s at to acheive those speeds.
 
I just finished my 6.5 Grendel build and I went with the 22" JP Supermatch barrel kit. I took it out for the first time Saturday and so far I really like it. I was getting .75" 5-shot groups with factory Hornady 123gr SST's. I don't reload and those were the only rounds I have found at the local stores. I ordered it in November and it took about 4 weeks to get it.
 
This is the 5-shot group with the 22" JP Supermatch Barrel using Hornady 123gr SST's -


IMG_4036.jpg
 
jd65 said:
I just finished my 6.5 Grendel build and I went with the 22" JP Supermatch barrel kit. I took it out for the first time Saturday and so far I really like it. I was getting .75" 5-shot groups with factory Hornady 123gr SST's. I don't reload and those were the only rounds I have found at the local stores. I ordered it in November and it took about 4 weeks to get it.
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Where did you order it from? Straight from JP?
 
I have had 24, 20 (19.5 technically), and 18 inch barrels. Overall, the best compromise between performance and mobility is the 20 inch barrel. I would only recommend the 24 inch barrel if you only shot from a bench and never did much moving around. The small gain in velocity of more than offset by the tremendous decrease in manuverability. Franly, the 24 inch tube is just way too clumsy. A proper loading with the 123 grain bullet will keep that bullet from going transonic until well after 1200-1400 yards with a 20 inch barrel in any case.

IIRC, Bill Alexander's (the primary "inventor" for the Grendel) favorite barrel length for the Grendel is the 20 inch barrel. That alone should decide it for you.
 
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SKYNET KC said:
Where did you order it from? Straight from JP?
Click to expand...

I ordered directly from JP. I chose my options for the barrel kit through JP's rifle builder and then submitted it. I then called JP and spoke with Ben. We went over the options again, I asked the questions I had, then paid for it. Four weeks later it was at my house. I probably would have received it sooner but I ordered it Cyber Monday and it shipped the week before Christmas. My experience with them was great.
 
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jd65 said:
I ordered directly from JP. I chose my options for the barrel kit through JP's rifle builder and then submitted it. I then called JP and spoke with Ben. We went over the options again, I asked the questions I had, then paid for it. Four weeks later it was at my house. I probably would have received it sooner but I ordered it Cyber Monday and it shipped the week before Christmas. My experience with them was great.
Click to expand...

Where did you get your bolt from? They don't include them with the barrel do they?
 
If all you're doing is punching paper, I'd suggest a 24" bull barrel all day. Like others have said if you'll be moving around with it at all, then you'll want to go with a shorter lighter caliber.

Where will you shooting?

A 16" will get you to 800 yards on paper, especially if you'll be shooting at higher elevations. LRRPF52 (he's on here and 65grendel) has a thread over there were he was stretching his 16" AA barrel out past 100 yards in the rocky mountains not to long ago.

I've got a 24" Precision Firearms build with a bull barrel. It's a lug to carry around and I'm a pretty athletic guy. I've got a 16" and 20" Lilja barrel on its way.

The 16" medium contour will be my brush gun and SHTF gun. And the 20" AR740 contour will be my all around gun.
 
If I had unlimited funds, and was starting a Grendel build, I would probably get a 20-21 inch light weight, fluted barrel, then have a lightweight carbon fiber forend to mount under it. I would want the JP captive buffer/spring unit, and rifle length gas system with an adjustable gas system. I would also use the lightweight JP bolt carrier. That would make for a very handy, lightweight rifle, that has just a touch more barrel length, but not too long.

Many newer shooters who want to use rifles for various matches like practical rifle or 3-gun fail to take into account how long it can take to pull a longer barrel out of various ports, and get around various barricades.
 
20 dose everything I need it to do. The 108 scenar gets me to a grand with little problems and it's still compact for hunting.
 


What barrel and gas length is everyone running? What is your MV and what does your brass look like?
 
Im running a 16 inch BA. With 123g Nosler CCs and CFE223 im getting 2433 fps. No pressure signs on the brass. 129g ABLRs over XBR give me about 2100fps. Again no pressure signs
 
Back in 2014 common wisdom was that you needed a long barrel to get the most of the cartridge, but there's a ton of evidence today that short barrels do surprisingly well too. The venerable LRRPF52 has proven that even a 12" Grendel is capable of reliable hits at 800 yards. Still, if you're looking to shoot primarily at targets from a bench and don't need the maneuverability, a 20" or longer barrel is a safe bet for easy hits. The extra velocity definitely helps as the distance grows.

Personally, I like my gas guns to be a little more versatile, so I settled on an Alexander Arms 18" fluted barrel. It makes for a relatively lightweight 400 yard hunting rifle that can still reach out to 900+ yard targets when I have access. If I lived in a free state, my first build would be around a 6.5G 12-14.5" barrel which would be used as a permanent suppressor host.
 
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Xjtony said:
Im running a 16 inch BA. With 123g Nosler CCs and CFE223 im getting 2433 fps. No pressure signs on the brass. 129g ABLRs over XBR give me about 2100fps. Again no pressure signs
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8208 XBR is an unusual powder choice for that 129gr; generally it’s better used with lighter bullets below 123gr. Your CFE223 is a much better performer with that 129 ABLR, although if you can find Lever it’s the best match for that bullet. It’s such a long bullet that it requires a dense high-energy ball powder like Lever to get the best performance out of it.

My Lever load with that bullet is a little warm, but does 2240 fps from my 12.5” barrel.
 
Yondering said:
8208 XBR is an unusual powder choice for that 129gr; generally it’s better used with lighter bullets below 123gr. Your CFE223 is a much better performer with that 129 ABLR, although if you can find Lever it’s the best match for that bullet. It’s such a long bullet that it requires a dense high-energy ball powder like Lever to get the best performance out of it.

My Lever load with that bullet is a little warm, but does 2240 fps from my 12.5” barrel.
Click to expand...
Do you think WC844/h335 would be better for 123s than 8208?
 
supercorndogs said:
Do you think WC844/h335 would be better for 123s than 8208?
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FWIW I'm using 26.8 gr of Benchmark with the Hornady 123 gr HPBT American Gunner projectiles Midway sells.
I get 2275 fps out of a 12.5" BA barrel. No pressure issues and good accuracy since that barrel seems to like those bullets.

8208 can work with 123's but you can hit the wall between safe and unsafe very quickly. Lots of threads on the grendel forum about this.
 
supercorndogs said:
Do you think WC844/h335 would be better for 123s than 8208?
Click to expand...
I expect it'd work well, but haven't used H335 with that combo.

I do use 8208 with 123gr and lighter, and it works fine there (although Lever can still gain ~100 fps in my 12.5"); it's the heavier bullets that 8208 is not as well suited to.
 
Yondering said:
8208 XBR is an unusual powder choice for that 129gr; generally it’s better used with lighter bullets below 123gr. Your CFE223 is a much better performer with that 129 ABLR, although if you can find Lever it’s the best match for that bullet. It’s such a long bullet that it requires a dense high-energy ball powder like Lever to get the best performance out of it.

My Lever load with that bullet is a little warm, but does 2240 fps from my 12.5” barrel.
Click to expand...
XBR under a 129G ABLR is a fairly common combo on some other sites. Its a bit slow but I loaded these for hunting and at my current MV I can keep velocity up above 1300FPS ( Nosler states this speed as minimum for reliable expansion) out to over 700 yards. I live in Utah so I do have density altitude on my side too :) I ran with this load because it was sub MOA in my set up and had good SDs. I've only been loading for a few years so when stuff becomes more available again I will work some other powders for these.
 
H4895 an alternate for 129 ABLR’s, though prefer CFE for same, with consideration for changing temps in Tx. Have Lever on hand for some further testing. AR Comp is about perfect for 120/123’s in my experience with 6 Grendel barrels between 18-24”. Temp stable and very accurate with well developed loads. All said, I reach for my 20” Wilson, Bartlein or Satern more often than not. They just seem to sit a bit more solid with bipod and small rear bag.
 
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Good timing on the thread from the dead.
I just bought the last piece of the puzzle for my 6.5G build. I have a 20" Satern that I cut/crowned the threads off of and it will go on a FightLite lower/Gibbz G4 upper. Should be a fun little hunting gun for the areas I can actually hunt it (sadly not in my state). I'm hoping that I can get the 1100 stock ,that I picked up for short money, to work on the rifle. Just to class it up a bit.
 
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I have a Stoner 20" Upper and a homebuilt 24" from Stoner parts. I prefer and suggest the 20".

I got carried away with hotloading because the case simply wasn't showing serious pressure indicators. The 20" handled the loads, but the 24" didn't; the extractor broke. Close as I can tell, the problem was the additional 4" of barrel, adding that much more dwell time under the excessive pressure.

The 24" is fixed with a JP Improved Grendel Extractor, and will be reserved for Speer 90 TNT loads from now on. The thinking is that these loads should reduce pressure and dwell time due to shorter transit time. If your cases are showing heavy carbon on the necks, that indicates that it is overgassed and extracting while serious pressure still exists in the barrel. The solution to this is to reduce charges.

There's probably an issue with the same (previous 120gr Speer Gold Dot loads) loads that broke the 24" extractor, so those loads have been disassembled and reloaded to eliminate hot loads according to Speer load data. I have a spare identical barrel, and intend to shoot the heck out of this rifle.

FWIW I get hold of the first Frontier 123gr FMJ loads. They shot hot, and accuracy was not great. For a 'military' load, that may be acceptable; but that's not the kind of shooting I prefer.

Greg
 
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Greg Langelius * said:
I got carried away with hotloading because the case simply wasn't showing serious pressure indicators. The 20" handled the loads, but the 24" didn't; the extractor broke. Close as I can tell, the problem was the additional 4" of barrel, adding that much more dwell time under the excessive pressure.



Greg
Click to expand...

It’s usually your gas tuning that makes one barrel harder on extractors than another. Peak pressure has dropped long before that last 4” of barrel and that’s not causing your issue; more likely the rifle is slightly over gassed, causing earlier extraction with more force on the extractor.

Or, the most likely explanation is you’re looking at a sample of one and the failure doesn’t mean much of anything. Maybe just a bad part, don’t read too much into it, and anyway that’s a really poor way to assume a load is over pressure. Extraction force is not a function of chamber pressure, it's a function of gas tuning.
 
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Yondering said:
It’s usually your gas tuning that makes one barrel harder on extractors than another. Peak pressure has dropped long before that last 4” of barrel and that’s not causing your issue; more likely the rifle is slightly over gassed, causing earlier extraction with more force on the extractor.

Or, the most likely explanation is you’re looking at a sample of one and the failure doesn’t mean much of anything. Maybe just a bad part, don’t read too much into it, and that’s a really poor way to assume a load is over pressure.
Click to expand...
I agree. I'm running a H3 Geissele buffer and spring in one and a rifle buffer a spring in the other. The one with the Geissele Super 42 buffer and spring as an H1 and H2 tore up cases to the point of bending case rims so they were unusable. As an H3 it slows everything down enough that tearing up cases is no longer a problem.
 
I have an 18" Satern/Brownelles with mid gas. I was thinking of getting it cut back to 16" and threaded. I ordered an 18" Criterion hybrid contour, 18" with rifle length gas.
 
Yondering said:
It’s usually your gas tuning that makes one barrel harder on extractors than another. Peak pressure has dropped long before that last 4” of barrel and that’s not causing your issue; more likely the rifle is slightly over gassed, causing earlier extraction with more force on the extractor.

Or, the most likely explanation is you’re looking at a sample of one and the failure doesn’t mean much of anything. Maybe just a bad part, don’t read too much into it, and anyway that’s a really poor way to assume a load is over pressure. Extraction force is not a function of chamber pressure, it's a function of gas tuning.
Click to expand...

Normally I'd agree completely with this, and I'm pretty sure an adjustable gas block would indeed solve this problem. I just haven't seen much about this problem, the barrel is a very common one - AR Stoner, and if the problem was a common one, I'd be thinking I'd be seeing a lot more about it.

I think this is about hot loads because I'd been doing my load research on posts about folks who've been loading the 6.5G for bolt guns, which don't have this AR problem. I was trying to turn my 24" AR into something more like a bolt gun and get those super duper velocities. As it turned out the extractor broke literally when I went .1gr over the listed max charge (by Speer). I think my problem was caused by my looser grasp on reality, and recommend that for other shooters, they follow your advice to the letter.

All my hot loads have been taken apart, and redone using loads within the published range, so I expect that with them and the new extractor, I should be back in business. Better safe than sorry, and I had been exceeding recommended loads along the process.

I do greatly appreciate your attention and assistance.

Greg
 
Greg Langelius * said:
Normally I'd agree completely with this, and I'm pretty sure an adjustable gas block would indeed solve this problem. I just haven't seen much about this problem, the barrel is a very common one - AR Stoner, and if the problem was a common one, I'd be thinking I'd be seeing a lot more about it.


Greg
Click to expand...

Sorry but that’s a pretty poor analysis of your own rifle’s performance. You’re basically assuming that your rifle isn’t over gassed because you haven’t heard other people saying theirs is over gassed. There are several things wrong with that, but the main point is to tune your rifle for your loads; this is dependent on many factors outside the control of the barrel manufacturer and if you want the ability to run max loads safely then tuning is a necessity. You already have evidence the rifle is probably over gassed; the hot load isn’t the main problem and neither is the barrel length.

BTW - wanted to add that I appreciate your level headed replies and comments.
 
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I have an 18” barrel on my AR15 Grendel. Able to get plenty of velocity with hand loads. I use 123 Eld-Ms.
 
This subject regarding my rifle has been discussed on this site before, several times.

Now I have a new problem; contradictory advice.

The sooting of the necks and the probability of excessive loads has been advised and agreed to several times already.

You're not solving my problem by adding to the confusion. I am forced to accept that your advice can easily be correct. This leaves me with a quandary.

I thank you for your advice, and have decided to go with the solution I have mentioned already, as it has been suggested to me several times previously by several posters here.

I'm sorry, but I'm not going to tear my rifle down and incorporate a new (to me) complication of an adjustable gas block; not just yet.

One of two things (at least) will happen. A) I'm dead wrong and the rifle will continue to exhibit the same bad habits (sooting, etc.) and break again. In which case, I'll add an adjustable gas block. But not until then; my own solution is untested as yet and should be. Or, B) It's fixed, there will be no further problems, and we're done here.

In any case, we're done here. Have a nice day.

Greg
 
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