Barrel Length/Twist Question and anything else you wish to add

[BgDnTX]

Hello to all.
I have decided to get into the 6.5 world. I have a Colt 6920 1:7, M&P15TS 1:7, and a Daniel Def 1:7 coming shortly
So I have focused on a complete upper to start out and believe I'll put it on top of the M&P. I think Radical Firearms is my choice for a lower priced upper to start.
The only question for now is what length barrel? Either the 20" or 24"? My interest is mainly accuracy at 1000m, 600m, 400m. (I have access to a 1000yd range) and then knocking down a skinny TX whitetail with a neck/head shot (my 5.56s do that with no problem )
I understand that a longer barrel offers faster, maybe more accurate, and so on. And I am not concerned with weight for this gun since I will bench shoot and hunt on my own property with little hiking.
So, 20" or 24"? And how about twist? 1:8? or is 1:9 in these lengths good to go?
Thanks in advance for your thoughts.

[VASCAR2]

I bought a 20" and the 24" only gains about 80-100 FPS second over a 20". Normally you can get 2450-2500 FPS out of a 20" barrel with a 123 grain bullet. A 123 grain bullet with .510 BC should be supersonic to over 1000 yards even at sea level out of a 20" 6.5 Grendel. I have a 1:9 twist Shilen barrel which stabalizes 123 grain bullets fine out to 1000 yards but if you intend on shooting heavier bullets (139-140 grain) I'd recommend the 1:8 twist.

[BgDnTX]

Thanks VASCAR2, very good and specific info. Even though we're talking just 100fps, that is encouraging me to go ahead with the 24". Appreciate the reply.
I am into pistols big time and understand in them a longer barrel is not always necessary, or that it improves performance that much. ie. the 357 magnum operates well within 4" to 6" barrels and beyond that there is little increase in performance. This is what I was considering in the 20/24 decision.

[VASCAR2]

I just checked the Hornady Ballistic App and the 123 grain bullet at 2450 FPS at sea level still has 1090 FPS at 1200 yards. I'm loading 31.0 grains of CFE223 with CCI 450 primers with 123 grain Nosler CC and I get an average of 2450 FPS and my rifle shoots better than I can with this load. This is not a hot load at all in my 20" Shilen, the high ballistic coefficient of the 6.5/264 bullets really helps in shooting long range.

[BgDnTX]

Yeah. I have focused on CFE223 since that seems to be a common or preferred powder and the Hornady or Nosler bullet in the 120g area as my starting reloads. I load a lot of handgun so I'm ok with that; the long gun reloading will be a learning curve.
Sounds like your 20" is doing about everything that needs to be done. May have to rethink going to a 24".

[JASmith]

You want to go to 1,000 yards? Try this 17.6" barrel: http://www.65grendel.com/forum/showt....6-quot-Barrel

[bwaites]

You want to go to 1,000 yards? Try this 17.6" barrel: http://www.65grendel.com/forum/showt....6-quot-Barrel

I'm guessing he isn't up at 5000-6000 feet like LRRPF52 is, though!

[JASmith]

Betcha it would still be OK on a wintry day in Death Valley!

One of us needs to run residual velocity and drift calculations with a handy dandy ballistics calculator...

[Joseph5]

I have a 22 inch Lilja barrel and I am getting 2640-2650 fps with 123 gr bullets, and 2950 fps with 100 gr bullets. If you use the Google search feature located in the sticky post at the top of this forum and look up Bwild97 he did a lot of reloading work and was getting 2700 fps with some 123gr loads. If you want to have the best results with accuracy at extended ranges I would urge you to look at an upper with a premium barrel. Alexander Arms and Precision Firearms are well known for producing high quality uppers with premium barrels that are awesomely accurate. You could also assemble an upper your self with quality components.

[pdq5oh]

I have a 20" 1/9 barrel that's very accurate. 123 SSTs are its favorites. At least with my hand loads. Factory AMAXs shoot very well, too. I've had good luck at long range (1000 yd plates) with the Berger 130 Hybrids as well. I think the 140 gr bullets are too heavy to get the velocity needed to take advantage of the higher BCs, though the Hybrids have a BC as good as most heavier, longer bullets.