7BC build barrel advice

[av8nAK]

Hey, guys. FNG here looking to build my first custom hunting rifle. I’m not trying to build the ultimate ultralight rifle, but want a short overall length do-it-all Alaska rifle that will travel up some mountains. With that in mind, I’m leaning towards a 7BC. I already have a .338WM for bears. Here are my planned components at the moment. So far only the HNT26 stock has been purchased.
Stock: MDT HNT26
Action: Falkor LW7
Trigger: TriggerTech Diamond?
Scope: 3-18x44 ZeroTech (deposit paid)
Barrel: ? (I’m wanting a 16” barrel.)
Rings/bases: ?
I like the idea of Proof’s PXT rifling, especially for the higher pressure of the 7BC, but in keeping with the short overall length I’d like to pair it with an OTB suppressor. Right now I’m thinking the OG 30 which should be out soon. The Proof barrel isn’t going to pair with that particular suppressor. I’d like to keep the barrel weight around 2.5 pounds if possible. I’m considering a steel contour similar to a Bartlein 2B (huge lead time), Hart #3, or ACE #1 just so it’s not super thin. Or is that too thin? I’d like to be able to shoot at least 5 rounds at the range before having to let the thing cool so I don’t get bullets walking about from heat. In anyone else’s experience is that doable with those contours? With fluting that might get barrel weight down to around 2.5 pounds? My math puts total weight of the rifle with scope and suppressor at roughly 8.3 pounds or so if I can do the 2.5 pound barrel. That’s acceptably luggable. Given my goals, what would you do differently? Barrel advice? Thanks!

 

[IrkedCitizen]

Carbon is pretty but that's about all you get from it. Isn't PXT rifling just rebranded Gain twist? Gain twist has been around for a while

I don't necessarily buy in to the 7bc hype but if that's what you want to get then by all means. If I was building a 7mm long action I would go with the 7-300prc and shoot Sierra 185gr TMK bullets. ADG brass has headstamped brass available for it.


You can buy a stainless steel blank from Patriot Valley Arms with several contours to choose from. Lead times are not horrible because the blanks are on the wall ready for contouring. Then find a gunsmith to chamber it.

OBW - 7mm blanks All Contours

[email protected]

patriotvalleyarms.com

Or you can buy a prefit barrel and he offers both 7bc and 7-300prc.

Osprey 7mm Prefit Barrels - All Actions

Precision rifle prefit barrels for all actions, custom ordered and ready to install. No machining or gunsmithing required. Match winning Osprey barrels by Patriot Valley Arms; we Engineer Repeatability. 100% Made in USA

patriotvalleyarms.com

I've been using his .750" taperless contour lately. You can see weights that people have posted in the thread below

Thread 'PVA Taperless Tikka Pre-fit weights'

Jul 16, 2024

For anybody that has a 0.75" or 0.68" taperless PVA Tikka prefit, would you mind sharing the caliber, weight, length, and fluting of your barrel?

• gtriple
• Replies: 56
• Forum: Firearms

• 

 

[UncleNommies]

Unless you are dead set on the OG 30, there are other options for suppressors on a Proof Carbon barrel contour. Dead Air sells the Nomad OTB Ti which is rated for 7bc down to a 16 in barrel. Also airlock sells the Zero Gravity 7, which is not a OTB but it's only adds 4.8 inches to the barrel length and it's 6.6 oz.

 

[av8nAK]

Carbon is pretty but that's about all you get from it. Isn't PXT rifling just rebranded Gain twist? Gain twist has been around for a while

I don't necessarily buy in to the 7bc hype but if that's what you want to get then by all means. If I was building a 7mm long action I would go with the 7-300prc and shoot Sierra 185gr TMK bullets. ADG brass has headstamped brass available for it.


You can buy a stainless steel blank from Patriot Valley Arms with several contours to choose from. Lead times are not horrible because the blanks are on the wall ready for contouring. Then find a gunsmith to chamber it.

OBW - 7mm blanks All Contours

[email protected]

patriotvalleyarms.com

Or you can buy a prefit barrel and he offers both 7bc and 7-300prc.

Osprey 7mm Prefit Barrels - All Actions

Precision rifle prefit barrels for all actions, custom ordered and ready to install. No machining or gunsmithing required. Match winning Osprey barrels by Patriot Valley Arms; we Engineer Repeatability. 100% Made in USA

patriotvalleyarms.com

I've been using his .750" taperless contour lately. You can see weights that people have posted in the thread below

Thread 'PVA Taperless Tikka Pre-fit weights'

Jul 16, 2024

For anybody that has a 0.75" or 0.68" taperless PVA Tikka prefit, would you mind sharing the caliber, weight, length, and fluting of your barrel?

• gtriple
• Replies: 56
• Forum: Firearms

• 

That’s good info! Thanks! The reason for the 7BC is to get decent velocity with a 16” barrel. I’m going for a compact package. I have a 12.5” 6.5CM that’s a lot of fun, but my 143ELD-X is leaving the muzzle at about 2350fps. Good deer rifle out to probably 400 yards at which point I’m dropping dangerously close to minimum expansion velocity. The 7BC would be a step up.

Unless you are dead set on the OG 30, there are other options for suppressors on a Proof Carbon barrel contour. Dead Air sells the Nomad OTB Ti which is rated for 7bc down to a 16 in barrel. Also airlock sells the Zero Gravity 7, which is not a OTB but it's only adds 4.8 inches to the barrel length and it's 6.6 oz.

I’m not set on the OG. Just wanting short overall length. I‘ve been looking at that Airlock one. That’s a good option and would also work on my 6.5 that won’t take an OTB suppressor due to fore end. If they ever get it in stock.

 

[IrkedCitizen]

The 7-300prc is no slouch in the speed department. Good chance of 2900fps from a 16" barrel

 

[UncleNommies]

That’s good info! Thanks! The reason for the 7BC is to get decent velocity with a 16” barrel. I’m going for a compact package. I have a 12.5” 6.5CM that’s a lot of fun, but my 143ELD-X is leaving the muzzle at about 2350fps. Good deer rifle out to probably 400 yards at which point I’m dropping dangerously close to minimum expansion velocity. The 7BC would be a step up.

I’m not set on the OG. Just wanting short overall length. I‘ve been looking at that Airlock one. That’s a good option and would also work on my 6.5 that won’t take an OTB suppressor due to fore end. If they ever get it in stock.

I feel you on that! Im shooting for compact as well. I wish manners would inlet the pro pack folder for a tikka. I'm building a 7bc off a Tikka action with a Proof barrel (still waiting on this one 2 months after ordering lol) I'm narrowed down between the two supressors I listed!

 

[BBob]

Isn't PXT rifling just rebranded Gain twist? Gain twist has been around for a while

No, it’s not your std run of the mill linear gain twist. Apples to Oranges. Not saying their claims are all valid but it’s different.

 

[av8nAK]

The 7-300prc is no slouch in the speed department. Good chance of 2900fps from a 16" barrel

I feel like I would be blowing so much powder out the barrel that even if I missed it would probably die from 3rd degree powder burns. It might even kill and grill in one step!

 

[IrkedCitizen]

Doesn't bother me if I waste a few grains of powder

 

[AlaskaRed]

I put a PBB on mine 17.5" and a nomad ti otb. It comes in around 22.5" barrel length suppressed. My .02 put it on a tikka action for obvious reasons.

 

[scaast]

If you're dead set on a carbon fiber barrel, check into BSF barrels. I put an 18" BSF CF barrel on my 300 WM build and have been really pleased with it. If you're a veteran or military, they have a generous discount as well.

 

[swampy14]

I’m going to get an 18” PBB in 7BC just haven’t decided on contour. It’s either going to be #2 sporter fluted or .750 Taperless paired with DA nomad OTB can

 

[wind gypsy]

The new proof barrels are intriguing and their marketing would make that a good fit with a 7bc. Not sure I buy all the hype yet but time will tell.

Benchmark #4 is my favorite contour for weight conscious, 20" or shorter, suppressed use. It's not as heavy on the breach end as the bartlien/Krieger/ACE contours and should have over 0.70" shoulder at 20" finish, more with shorter finish lengths. They had a 4 month lead time last i looked.

Osprey 0.750 taperless weighs almost exactly the same as a benchmark #4 @ 18" too. Either would fit within your 2.5# or less goals.

I would have gotten a crbn over a hnt26 with a high recoiling rifle but understand others disagree and highly value the folder.

Get a rough diamond rather than a diamond if you're going that direction with trigger tech. Bottoming out the pull weight seems to come with a little more reliability issues. I'd prefer a 2 stage with some overtravel I think but I've only ever had timney and TT single stages on m700s and haven't wanted that bad enough to replace the diamond on my last m700 pattern rifle.

 

[Grillnugz]

Buy an action that has a lot of shouldered pre-fit options. With preferred barrels making shouldered tikka prefits, the tikka action is a good choice. PTX is currently available in tikka, defiance and zermat. Kelbly, impact have prefit options as well. I own a Kelbly atlas lite and it’s a nice lightweight action, love the mechanical ejector. The atlas is pretty good value too. Mac bros element is super light, but no prefits last time I looked. Rem700 clone actions are super nice, but factoring cost of bottom metal, trigger, magazines, etc the tikka is probably the best platform today. Save $500-1000 with little to no performance loss.

I like the embrace of the high pressure steel case tech. With the release of the new 6.5 +peak ammo, why not go 308, 30-06 or some other classic round, I’m guessing ammo for these should be coming soon. If the +300fps turns out to be real those old 30s will turn into 300wm. Plus you’ll have ammo flexibility if you forget the +peak at home.

I own trigger tech and bix n Andy triggers. Both are excellent. Consider a two stage.

 

[SloppyJ]

If it were me, I'd go with the Proof PXT just to see how it unfolds. Definitely not the same as the gain twist we are used to see where there's a difference of a couple inches of twist over the entire barrel. From the information I have read the proofs go from like 1:500 twist to 1:7 or whatever the finished twist rate is. That's quite a bit different than the normal gain twist of the past.

They have some tall claims so I'd like to test one and see if they can put their money where their mouth is. They seem specifically dialed in for these high pressure rounds and they're not much more than a normal steel barrel by the time you get it cut, threaded, and chambered. What's to lose?