BCM SS410 1/8" Barrel with 70 gr TSX

[Malletor]

I'm planning on building a recce and was looking at the BCM uppers.

Does anyone have any experience with the BCM SS410 16" 1/8" barrel using 70 GR TSX?

I know that the TSX is much longer than other bullets so I don't know if I'm going to have to use a BCM BFH 1/7" to stabilize the long 70 gr TSX's. It is critical that this gun accurately shoot this ammo because it's primary use will be hog hunting.

Thanks guys!

[Onyx Z]

You're fine. They aren't all that much longer than 77gr SMK's, which shoot just fine with a 1/8 twist.

[Malletor]

Are you speaking from personal experience or is this just speculation on your part?

Just wondering

[gun71530]

I'm on my phone, so I can't post a link, but there is a massive thread in the hunting subforum about the 70 grain TSX.

Sent from my DROID X2 using Tapatalk 2

[wahoo95]

1/8 shoots 70gr TSX just fine

[Malletor]

I've read almost all of the posts in the hunting forum but there are very different opinions on the 70 gr TSX performance in a 1/8" twist so I was wondering if anyone had any real personal experience with the barrel I was looking into getting.

[wahoo95]

They shoot fine from my Rainier Arms 1/8 and my White Oak 1/8. Assuming BCM is in spec and properly made to 1/8 I can't see why it would have any issues unless you simply have a picky barrel. Could be their barrel didn't care for whatever load they were using overall. Only true way to find out how any given bullet or ammo shoots from a particular barrel is to shoot it.

[thopkins22]

Chances are that your 1/8 will love them unless it was cut slow.

Per Barnes, they're fine in 1/8 and I've shot them without issue in my 1/8's(a BCM and a White Oak,) but worst case scenario the 62gr. TSX is a beast as well...and frankly I have no qualms about the 53's.

[markm]

Krieger makes BCM barrels. They'll be rifled correctly.

Out of curiosity, why are you choosing this bullet? I've never tried them, so I'm just curious to know if they do something specific that you like.

[RyanB]

Krieger makes BCM barrels. They'll be rifled correctly.

Out of curiosity, why are you choosing this bullet? I've never tried them, so I'm just curious to know if they do something specific that you like.

They expand to 350m from an 18" barrel.

[markm]

They expand to 350m from an 18" barrel.

Hmmmm.. yeah. I googled the round. Interesting.

[Malletor]

Yeah the reason I'm very interested in the round is because it'll be used on hogs up to 300 lbs and the round is very proven for hunting medium sized game.

[markm]

Sounds like the perfect round for you then.

[BobinNC]

You can calculate Bullet Stability yourself here: http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

The only thing you'll need is bullet length, which for the Barnes 70 Gr TSX 1.03". You can then plug in different muzzle velocities and atmospheric conditions to see when and if you loose stability. BTW - The 70 Barnes TSX is stable in a 1-8 Twist barrel even when the starting FPS is a slow 2500 FPS...

[markm]

Don't start a bullet stability fight! :dance3:

We just had one of those last week.

[Malletor]

Thanks for the online calculator. It's very helpful. I think I'm gonna go ahead and go with the ss410 barrel. Thanks for all the recommendations guys.

[vicious_cb]

For a 1/7 twist. I could not find one for a 1/8.

http://www.box.net/shared/static/6tordomos4.jpg

[markm]

Interesting chart. Odd that stability goes up again as velocity drops below 1100.

[thopkins22]

I dislike that chart. As we learned in the other thread, things are either gyroscopically stable or they are not. "Over stabilization" is a concern only if your bullet might rip itself apart.

Per that chart, a 70grain TSX is stable out of a 1/7 as long as you're pushing it 1500ft/s or faster. Which may be true because the JMB calculator agrees, giving it a higher GSF than that chart did at 1.526 and around 2000ft/s in a 1/8.

At some point(while interesting,) it's easy to get lost in the weeds when it simply doesn't matter beyond a stable/not stable determination.

[markm]

I dislike that chart. As we learned in the other thread, things are either gyroscopically stable or they are not. "Over stabilization" is a concern only if your bullet might rip itself apart.

That kinda caught my eye too. I don't see spinning a solid copper bullet to bits.


At some point(while interesting,) it's easy to get lost in the weeds when it simply doesn't matter beyond a stable/not stable determination.

It's important for those who were beaten for coloring outside the lines, send ATF clarification letters, and have fixations on their SBR engraving meeting a corrupt agency's requirements to the T!

[Laust]

markm,is this a fact> "Krieger makes BCM barrels. " I've been trying to find this out.

I brought the BCM SS410 16" 1/8" Ionbond barrel. I asked BCM,they aint talkin, and all others "speculate" and say Criterion,they won't say either,i know Criterion broke off from Krieger.
So exactly what is the verdict?

[markm]

I don't know any more than that. What is in quotes is what I was told.

I'd love to shoot one of those BCM SS barrels to see if we could make it sing with our 77 SMK load. But I need another AR like a hole in the head.

[Laust]

Thanks markm,i stocked up on some BH 77 smk for this build,just got my rail today,last piece i was waiting on. And it's 6 degrees outside.