Guns & Outdoors Forum

I'm ordering an 18 inch barrel for the bullpup I'm building. This will be a deer rifle so I'll want heavier bullets. What twist rate should I use 1:7 or 1:8?

1:7.


You can’t over spin a bullet. But you can under spin. But either would do. I’d just er on the fast side if both are available.

Both of mine are 7.5 twist. They shoot 105-108 grain bullets very well and both are sub MOA shooters with 75 grain bullets. I’d go with 7 twist if those are the options.

Mine is coming with a 7.5T as it was the only option. But, I’d choose 7T of the two options you have.

There are too many options to choose from! Please help by looking at the selection they have, I have no experience at this.

https://www.x-caliber.net/custom-ar-barrel

Buy a 6 arc barrel ready to go and plug the gas hole.

I've looked at the inexpensive barrels but they don't float my boat. First they are heavier than I want, this rifle should be just over 6 lbs scoped.
Second, I don't want gas blocks. Third, they are mil spec. The accuracy for this build will be in the barrel and bolt, I want sub MOA. If I judge this cartridge correctly, it will do 300 yards with less than 9 inches drop. Accuracy will be important. X Caliber Guarantees sub MOA if you use their parts. There is nothing inexpensive about this build but, it is the last rifle I'll...need (I can't believe I wrote that). This will more than likely replace my Savage 99. At 26 3/4 inches, 6.25 lbs it will rest on my chest and enable me to use my walking stick, be stable and hands free when still hunting in the woods.

BTW I was considering the bullet weight of 95-105 gr Hornaday SST or SGK.

If that’s the route you want to go, 7 twist is the fastest 6mm they list. That’s the one to go with. It’ll shoot 90-105 bullets just fine. And probably down to 75 if you ever wanted. Like I said, both of mine shoot 1/2 to 3/4” groups with the 75 Vmax and under an inch with 105 to 108 grain bullets. And both are 7.5 twist. Go with 7 twist.

ETA My AR in 6 ARC is a 20” CMMG. My bolt gun is a 22” Howa. Both have taken pigs and coyotes past 200 yards. At night…..

Screen grab the moment the shot broke. Coyote. 217 yards. 75gr Vmax just over 3200 fps. With the ballistic info in the scope, it was recommending 1.21 MOA hold up. So, call it 2.5”.

I ordered the barrel today 18 inch, Chrome molly with black Cerakote, 7t with 5R grooves, and ten straight flutes to cut the weight. It will be threaded should I decide on a muzzle break or suppressor. It should weigh 1.7 to 1.9 lbs. I ordered the bolt so they will head space the barrel and guarantee the accuracy. I wanted them to eliminate the gas system step but that wasn't possible, no gas port, no dimples, no logo.

Thanks guys

Who'd you go with?

X Caliber

Freezer wrote: ↑Thu Aug 07, 2025 10:33 amX Caliber

Not familiar with them, but hopefully it'll be a tack driver for you.

X Caliber had good reviews. If you order the bolt they offer they will head space it to the barrel and guarantee MOA or better accuracy. Less expensive off the shelf barrels are mil spec, heavy and hit or miss accuracy.

sounds like a plan