Discussion in 'Handloading and Reloading' started by Revilo, Jan 20, 2021.
The FTX .30-30 bullet is a polymer-nosed boat tail, I wonder if it is too long for the twist. (It shouldn’t be though.) I’ve loaded the green-tipped “Zombie” FTX bullets using Leverevolution and they haven’t had any issues in my 1970’s era 1894 Win.
Any tumbling with 150 or 170 gr or mono-metal bullets in your 336?
Question: Is it a MicroGroove barrel? (it will say on the barrel.)
The twist rate 1:10, unless you have a non-standard replacement barrel, so stabilizing those 160s is not a problem from that perspective.
There's either something wrong with the barrel, or the bullets. If there's nothing obviously wrong with the bullets (oddly different weights, visual deformity), it's the barrel. Have you checked velocity worth a chronograph?
Is the rifle new to you? Is this the first time trying the 160 FTX? Are you sure the barrel is lead free? Is the crown in perfect shape? Is the throat shot out? Can you see the rifling in the barrel? Can you see anything in the barrel that ought not be there?
Last time I seen a rifle do that part of the rifling in the barrel was gone
that’s kind of my thought... either a worn MG barrel, or a fouled barrel. I could just be the gun, too. My brothers 336 absolutely hated 150’s, but did well with 170’s... so you never know. Granted, it didn’t keyhole... that’s why I’m thinking the rifling isn’t, for some reason, stabilizing the bullet.
Still need to hear from OP on a number of questions.
.22 centerfire -- 16 grooves, .015" wide, .001" deep
.30 caliber -- 16 grooves, .030" wide and .002" deep (this would be changed in 1958 to 22 grooves .024" wide, and .002" deep; and then again in 1968 to 12 grooves, .040" wide, .0028" deep)
.32 caliber -- 16 grooves, .035" wide, and .0015" deep
.35 caliber -- 16 grooves, .040" wide, and .002" deep (this would be changed in 1968 to 12 grooves, .055" wide, .0028" deep)
Here is the link to the article incase anyone is interested.
Again, a .308 160 grs jacketed bullet will not keyhole from a .30 cal barrel unless the bullet is not .308, the barrel is not .308, or the rifling is seriously impaired.
There is nothing about micro groove barrels that would explain or cause a.308 160 grs bullet to keyhole. There is something wrong with the bullets or the barrel.
That's what I mean... the shallowness of the MG rifling. Someone at one time could have done something to the bore... it wouldn't take much.
It would take quite a bit to corrode or wear away the rifling.
Still wondering if the rifle is new to the OP. The bore wants slugging. If these are the first rounds through the rifle, it wants checking for things like whether someone rebored it to say, 35/30-30.
I was thinking something like lapping compound/bullets, or trying to remove excessive fouling with a stainless bore brush... something Bubba.
Yeah, it would have to be something severe like that.
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