TLC311-165RF Surprise

[Rooster59]

I understood the chunk of brass rod was to put in the brass case. They prescribed a steel rod with masking tape buffers to tap the bullet flat.

[62chevy]

It's been a while since I read it so maybe it's time for a re-read.

[62chevy]

Just went back for a refresher and the piece of brass he is talking about is a brass case that is fire formed to the chamber.

[Rooster59]

Just went back for a refresher and the piece of brass he is talking about is a brass case that is fire formed to the chamber.

Aha! That makes more sense than what I thought. Reading comprehension ain't what it used to be.

Did some checking last night and the plot appears to thicken. The bullets my buddy gave me to use for checking throat restriction are the Lee 309-170 and 312-185. The noses on both measure, with my calipers, around .297-.299". Both bullets drop into the muzzle up to the driving band. So far so good.

I loaded both in a fired case about half way into the neck. Inserted the case/bullet into the chamber and used the lever/bolt to seat the bullets further. This would start to give me an idea where the rifling becomes an interference fit with the bullet driving bands. It turns out both bullets show rifling marks from the nose to almost the driving bands stopping just short of the driving bands. That gives me a rough idea of how wide a driving band could be without contacting the rifling.

But, it also showed rifling marks on the bullet noses from the tapered area of the point, all along the cylinderical nose just shy of the driving band. That makes me think the throat area of the rifling is less than .300" and is definitely tighter than the muzzle.

[Rooster59]

Did some initial bore slugging work last night. I haven't done much of that so I call it initial, not final. The first slug went in the muzzle fine and worked its way down the bore to the chamber consistently. When it got to the throat end the slug took significantly more pressure to travel the last half to one inch. (I didn't measure it at that point). Finally it popped out. The groove diameter appeared to be .303" and the bore at .297".

I put another slug in and tapped it only about two inches into the barrel from the muzzle end. Removed it and measured. It came about at approximately .309" groove diameter and .300-.301" for the bore.

A third slug went all the way through again but I marked the hardwood dowel where the slug became nearly lodged. It was late so I didn't do any more measuring. So far it would appear the barrel is a consistent diameter until within an inch or less of the throat. Crazy.

[62chevy]

I would rather have that taper in the opposite direction. So how do you fix that, fire lapping, probably not or something else.

[Rooster59]

Ya got me! I plan to do some more detailed measuring. It may be that only the last fraction of an inch is actually that tight. My slugging expertise is dubious so a little more practice may offer more promising information but I don't know.

If there is no solution I guess this rifle will end up being a jacketed deer rifle and collects dust in the gun cabinet except for two weeks a year. Then I will just turn to my 45LC Puma trapper and Marlin 45-70 octagon for cast bullet shooting for fun. The odd thing is my wife's rifle with the same barrel exhibits the same characteristics albeit just a little less extreme.

[Ranch Dog]

Yeah, it seems to be a bit more trouble that it is worth.

[Rooster59]

A fellow forum member elsewhere offered to trade me some of his A model cast bullets for some of my B model bullets. His model A bullets came in today and I tried them. They will chamber with the barely perceptible kissing of bullet to rifling. That's with 2.032" brass. A tiny bit of trimming would allow chambering without notice.

More articulate slugging tonight has verified my results from last night. The slug goes all the way down from muzzle to breech until the last 1/8'-1/4". Then it has to be banged out the last tiny bit. If the slug is driven to that point and back out the muzzle it measures very nice .300"/.3085-.309". Seems like the breech end of the rifling and bore are swaged down a slight bit.

I'm going to try shooting some of these traded A mold bullets and see how they do with charges of 14-16gr of 2400 this weekend.

[Ranch Dog]

Sounds good and the rifle is probably a good candidate for fire lapping. Beartooth is the best source for those supplies.