Gunsmiths in Texas or North America for 7BC?

[swampy14]

Yeah I spoke with Matt at Hill Country Rifles and he seemed the most knowledgeable of the cartridge.
So definitely a level of confidence sending a rifle to him for work. He seems to believe in the cartridge especially for short barrels with suppressors

 

[Amathanda]

Yes, Matt is a good dude and a big supporter of the cartridge. He will build a nice rifle for you.

 

[PC356]

To each their own, long as the OP enjoys it is all that matters.
That said, if I was a bettin man I’d wager 7 BC isn’t stickin around.
Only time will tell.

 

[swampy14]

To each their own, long as the OP enjoys it is all that matters.
That said, if I was a bettin man I’d wager 7 BC isn’t stickin around.
Only time will tell.

I like it enough on paper to try it. If it doesn’t pan out then I can always put 270 barrel back on

 

[nm.otter]

Throat erosion and barrel life are of concern with 7 BC.

Is this concern based on empirical field data?

For a given projectile and MV, an 80k load will burn a fair bit less powder than a 60-65k load would.

 

[Fetty Wapiti]

Is this concern based on empirical field data?

For a given projectile and MV, an 80k load will burn a fair bit less powder than a 60-65k load would.

Observations of a rifle chambered in 7 BC. Saw some severe throat erosion and fire cracking at 130 rounds. Maybe a one off. I will stick with 7 saum for my shorter barrel 7's. Just makes more sense to me at this time.

 

[UncleNommies]

Ive read countless forums on the 7mm backcountry and the general consensus is, most people are making assumptions instead of looking into factual information provided by the manufacturer. The peak alloy case contains the pressure. As far as prefit availability, Proof Research offers 16.5" barrels for a Tikka T3x action, which I will be building off a .270 platform.

 

[swampy14]

Ive read countless forums on the 7mm backcountry and the general consensus is, most people are making assumptions instead of looking into factual information provided by the manufacturer. The peak alloy case contains the pressure. As far as prefit availability, Proof Research offers 16.5" barrels for a Tikka T3x action, which I will be building off a .270 platform.

I’ve debated the 16.5, 17 and 18” barrel lengths

 

[UncleNommies]

I’ve debated the 16.5, 17 and 18” barrel lengths

I wrestled with that as well, but my overall goal was the shortest package I can achieve with a suppressor. I dont think there was enough velocity loss from 18" to 16.5" to make me want to go 18"!

 

[Mike D Texas]

Throat erosion and barrel life are of concern with 7 BC. Others report accuracy issues and reloading troubles. 7 saum or PRC are better options in my opinion.

The early adopter issues have shown to be ammunition related, not cartridge related.


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[Mike D Texas]

Ive read countless forums on the 7mm backcountry and the general consensus is, most people are making assumptions instead of looking into factual information provided by the manufacturer. The peak alloy case contains the pressure. As far as prefit availability, Proof Research offers 16.5" barrels for a Tikka T3x action, which I will be building off a .270 platform.

Not surprising. It seems fuddery exists everywhere, including Rokslide.


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[swampy14]

The early adopter issues have shown to be ammunition related, not cartridge related.


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From my understanding Federal has addressed these issues and new ammo lots seem to be performing much better.

 

[swampy14]

I wrestled with that as well, but my overall goal was the shortest package I can achieve with a suppressor. I dont think there was enough velocity loss from 18" to 16.5" to make me want to go 18"!

From what I’ve seen you are correct, the 16” barrel is still humming at 2700+ depending on bullet weight

I am going to run the DA nomad OTB suppressor. Only adds about 4” inches of length muzzle forward. 18” barrel still about 22” finished length. Might split the difference with 17”

 

[UncleNommies]

From what I’ve seen you are correct, the 16” barrel is still humming at 2700+ depending on bullet weight

I am going to run the DA nomad OTB suppressor. Only adds about 4” inches of length muzzle forward. 18” barrel still about 22” finished length. Might split the difference with 17”

I will be searching for a OTB suppressor as well. I currently have a PTR Vent 1 that is 8.5 long, putting overall length around 25" with a 16.5" barrel. Ill have to check out that Dead Air!

 

[swampy14]

I will be searching for a OTB suppressor as well. I currently have a PTR Vent 1 that is 8.5 long, putting overall length around 25" with a 16.5" barrel. Ill have to check out that Dead Air!

Yeah that new OTB can was released at shot show two months ago.
I’ve seen it in person and it’s well designed.

 

[Lou270]

The whole idea behind the 7bc is that is even though is higher pressure, the case head is “standard” size so the bolt thrust is similar to a larger case - say a 300 prc at a lower pressure. Bolt thrust is pressure x case head area. So long as whatever action you are using can handle the bolt thrust of something like a 300 prc theoretically ok for 7bc. I would be leary of using one of the “optimized” actions for a given cartridge case for higher pressure than 65k since a lot of times metal is removed to make them slimmer/lighter to be perfect for the head size vs a generic action that is same size for all cartridges but different bolt face. An example off top of head would be something like kimber 84l. Trimmed very light to just fit a 30-06 type case and the 8400 magnum actions are beefier. May still work but should check with maker before assuming anything

I researched the 7bc some and the trick as somebody mentioned seems to be very tight tolerances. Probably because the steel case does not bump up as well. I think the hybrid fury case is probably more forgiving in this regard which is probably why the military went that route and the reality of needing tolerances in military guns for the conditions they need to work in. As others have mentioned HCR seems to be one of the makers pushing the round

Lou

 

[swampy14]

Very well stated Lou

 

[UnckleBob]

Actions built in the US aren't necessarily tested to anything. Proofing is only required in EU countries. And even so, assuming an action is designed to withstand up to 100k, increasing pressure from 65k to 80k means you're going from a factor of safety of 1.5 to 1.25. That gives you significantly less room for error when it comes to an overpressure event.

Its your face, but I don't like taking chances with what amounts to a controlled pipe bomb 5" from my face.

In the US, action makers are constrained by possible product liability lawsuits. With the possible exception of some custom action makers, every action sold in the US is tested to pressures well above Saami max for traditional cartridges.

More importantly, the max pressure on a 7BC is not the same as the max pressure on traditional cartridges. With the 7BC, a significant portion of the pressure is contained by the cartridge. That is why they are safe in modern actions. That is why we haven't seen news stories about blown up 7BC rifles.