20" Grendel barrel questions; gas port sizing, rifling, etc.

[FlashHercules]

Hi,

Longtime lurker, first time poster here. I've learned a ton browsing the forums here, but still have a few questions I couldn't find solid answers to. I'm working on my first 6.5 Grendel build, and could use some advice regarding barrels. I've decided on a 20" RLGS, but unsure about the gas hole sizing, and if rifling type affects the sizing at all.

From searching here, I've learned that a 20" RLGS barrel should be fine with a 0.080-0.090 hole, but I've found some 5r rifled barrels with smaller 0.070 holes. Does the 5r rifling increase pressure, requiring a smaller gas hole, or is this simply factory error (or cheapness)? I've heard some reports of increased velocity out of 5r rifled barrels, but being the internet, I remain skeptical.

I know that it's not necessarily bad for the gas hole to be too small, as one could always drill it out if the gun ends up being undergassed, but I'd rather avoid having to ship or bring a new barrel to a 'smith for work. Also, an overgassed barrel can be tamed with an adjustable gas block, negating the need for a 'smith or machinist (I don't have a drill press, and wouldn't trust any old Bubba with one to drill the gas port correctly.)

Finally, could anyone point me to any proven, decent quality, budget friendly barrels that are worth looking at? I've found lots, but would feel better buying one that's vouched for.

Thanks in advance, I'm looking forward to hearing your suggestions!

[A5BLASTER]

What's your budget?

There are lots of good barrels in that length.

Look at PF, Lijia,Shillen,Faxon,JP.

Probably more but those are the only barrels I know first had to be shooters and typically don't come with problems.

Hope this helps.

[VASCAR2]

http://www.bergerbullets.com/twist-rate-calculator/

[FlashHercules]

Thanks for all the info!

The barrels I was looking at were from Classic Firearms, as I've heard decent reviews of them (BCA) as of late. But, after the comments here, I'm seriously considering a Ballistic Advantage 20" DMR barrel instead. I was already aware of the different types/bolt faces, and had planned to buy a bolt from the same mfg as the barrel.

What about the 5r rifling? Anyone have any experience with it? Some have reported increased velocity vs standard cut rifling, though that could be attributed to a number of things. I'm really just trying to get the best bang for the buck, without poking the bear (aka my wife.) The cheaper the better, but I definitely don't mind spending a little extra for added performance, consistency, and customer support.

Thanks again for all the suggestions, I'm excited to kick this build off already!

[VASCAR2]

I have two 6.5 Grendel Faxon barrels with 5R rifling and in my opinion they are not as accurate as my Traditional button rifled Enfield type rifled chrome moly or stainless steel barrels with bimetal FMJ Wolf steel cased ammo. I haven’t tested my 5R barrels side to side with a traditional rifled barrel on the chronograph but my intial impression there is not significant difference in velocity. There might be 15-25 FPS difference for the same length barrel but to me it is not enough increase where I would only buy a 5R barrel. With monolithic or traditional cup and core bullets the 5R 6.5 Grendel barrels are accurate enough for me.

I would not buy a 5R only because I thought it would produce higher velocity. Unless you could test several barrels of both types of rifling I’m not sure you could make any definitive conclusion. If I knew I was going to shoot a lot of bimetal bullets in Wolf steel cased ammo I probably wouldn’t buy 5R rifled barrel. Whether five 5R barrels (two of mine & 3 Friend’s barrels) is enough to make a judgement it probably isn’t but why take a chance on a cheap barrel if traditional rifling is available. In my experience traditional rifled barrels are better with Wolf. Bill Alexander posted on this forum during his testing polygonal and 5R barrels didn’t shoot Wolf steel cased ammo as well as traditional rifling.

I think 5R is a little easier to clean but I’ve never had issues cleaning traditional Enfield button rifled barrels. I like my two Faxon 5R nitride 1:8 twist barrels and have no intention of getting rid of either. I haven’t shot much Wolf in my barrels but if I do shoot Wolf it’ll probably be in my 16” J&T distributing 1:9 twist CMV barrel with traditional rifling.

I think Ballistics Advantage makes good barrels and are a good value and I’d probably buy a BA over a BCA. To my knowledge BA does not sell 5R rifled barrels and that would not keep me from buying BA barrels. Everything I’ve read is positive on BA barrels accuracy.

We rarely see issues with gas port problems on 20” 6.5 Grendel barrels. Ballistic Advantage used a smaller gas port on their 12” 6.5 Grendel barrels because they assumed most users were going to use suppressors. Some users reported under gassed BA 12” barrels without suppressors. Last I read BA had resolved any issues with gas port size on 12” barrels.

[StoneHendge]

My only experience with 5R is my 308 RPR which is definitely a little on the fast side. But I have a few others that could also be described as a little fast. I would focus on the reputation and accuracy of the barrel maker. If you want a faster barrel, get a longer barrel

[grayfox]

All of my grendels, a 308 and a 6.5 Creed are 5R. I personally like the offset of groove-opposite-land but the most accurate rifle I have is a regular 6-land setup in 6.5 Creed, so not sure it makes a bunch of difference. The main thing is to get a good or great barrel from a reputable mfr who doesn't have a history of making the shooter do the QC... A couple hundred more for the barrel will save that much in ammo range trips and plain fiddling around.
The faxons I have shoot lots better than I do, the 6.5 Howa as well and the others too. I have basically given up trying to find the rock-bottom "economical" barrel any more. I can't quite go totally top notch (maybe some day!) but want to be in the upper, very-good tier.

I had a couple of BCA's but they weren't good enough shooters, I didn't have the short-chamber issues but they just didn't compare with the Faxon, Savage, Howa, Criterion barrels I have (heck even my Ruger AP in 243 is better IMO than the BCAs), so I got rid of them. Haven't looked back either.
While you can certainly buy once cry once, you should at least but once, cringe a little....... good barrel, good scope, good trigger, that sort of thing.

5R doesn't do well with Wolf but I don't shoot that anyway, I reload or do factory stuff, and those are doing great.

One more thing, I would definitely recommend to stick with the SAAMI spec chamber barrel and 0.136 bolt-face depth... the off-shoots didn't make my day so again, I sold 'em off.

[FlashHercules]

Thank you all for the insight. I didn't mean to sound like I was totally sold on 5r rifling because of additional velocity, I was really just curious about it. I'm glad to hear that it's "a thing," but that's not to say I'm going to run out and buy one. I just like to do my due diligence, and gather all the facts before making a decision. This will be my first build with accuracy and longer range shooting in mind, so I'm doing my best to get all the facts and make an informed decision.

It really does seem that the BA barrels would be the best route to take. The price is right, albeit a bit higher than I was hoping to spend, but I believe the benefits warrant the added cost. While I'm most certainly on a budget with this build, I'd rather buy something as important as the barrel once, than rolling the dice and possibly having to send it back and forth due to QC issues. The reason I asked all the questions about the BCA barrels is because I've had several folks tell me that they're a great value, but it does seem too good to be true. I'm sure they make a decent barrel, but I just don't have the time and patience to deal with a warranty department for who knows how long, only for a marginal savings.

Thanks again for all the helpful information and honest opinions, you've really helped me figure out the best way to go about this build.

[Popeye212]

Thanks for all the info!

The barrels I was looking at were from Classic Firearms, as I've heard decent reviews of them (BCA) as of late. But, after the comments here, I'm seriously considering a Ballistic Advantage 20" DMR barrel instead. I was already aware of the different types/bolt faces, and had planned to buy a bolt from the same mfg as the barrel.

What about the 5r rifling? Anyone have any experience with it? Some have reported increased velocity vs standard cut rifling, though that could be attributed to a number of things. I'm really just trying to get the best bang for the buck, without poking the bear (aka my wife.) The cheaper the better, but I definitely don't mind spending a little extra for added performance, consistency, and customer support.

Thanks again for all the suggestions, I'm excited to kick this build off already!

I have a Ballistic Advantage barrel and met a guy at the range yesterday. Both are tack drivers. On the gas system for the BA barrels they are ported for a carbine length buffer which is what I have and it cycles perfectly with the standard buffer and spring with starting reloads and factory ammo. They make good barrels at a good price. They are Type II so the more common and standard Type II bolts will fit. I also recommend a 1:8 twist which comes out on the Berger calculator as acceptable for 130gr. bullet. Any heavier than that the cartridge was not designed to work with. Hope this helps
Also for the BA barrels check these out for sales

https://www.armorally.com/product-category/ar-parts/ar-barrels/

https://www.graniteridgeoutfitters.com/searchquick-submit.sc?keywords=20%22+6.5+grendel

These barrels normally come with a gas block included so in deciding where you purchase them whether they include it or not is a factor.

[longlickfriends77]

I have a BCA 20” ss non fluted Barrel, when I build it I used a regular gas block, it ran fine did not have any malfunctions.
But it’s was throwing the brass always to the front so I put a heavier buffer in and it didn’t seem to help much. So I removed the gas blocked and measured the ID of the gas port hole, and it was .098.I installed a SLR gas block and closed it about half way and installed back the regular rifle buffer and ejection is perfect now.

[Jakal]

Look at Lilja, probably the best deal going. Top of line barrel and priced competitively.

http://riflebarrels.com/product-category/drop-in-barrels/ar/ar15/65-grendel/