Grinding the bottom of die or top of shell holder

[HiBC]

What sort of rifle did you get a new bolt head for?
For some,such as the SMLE,bolt heads come in different sizes,specifically to address this issue.
For some,such as Savage bolt rifles,the headspace of the rifle is adjustable by your local gunsmith.The barrel has a lock nut on it.

If you do modify the die or shellholder,its probably a good idea to write in the die box with a sharpy the modification.

For some folks,grinding the shellholder or die is done on a belt sander or snag grinder by hand.

There are a lot of unknowns there.

If you know the dimension you need to correct,example "I need .004"

And if you have access to a lathe or surface grinder ,if you can control taking a clean,square,known minimal amout without heat changing the colors of the steel,I don't think .004 off a die or shellholder is a big deal.

Generally,a used or Lee die is affordable enough to just go for it.

If you are needing .010 or more,I'd look real hard at what is going on.

You might Sharpy mark the locking surfaces of your new bolt head to see how the locking contact is.
Wouldn't it be amusing if all this was over a sharp corner on an outside corner interfering with a corner radius on an inside corner?

 

[Yosemite Steve]

The gunsmith suggested a small base die. The difference is close to .004". I figured a shell hold would be cheaper. The gunsmith said i will save money by not wearing out brass as fast and taking my barrel out will give me cockeyed sights. As it was it would close on factory with some feel but not much.

 

[HiBC]

OK,maybe.
Your Gunsmith has a lot more to see and work with than we do. We still have no idea what gun we are talking about.
If it will close on factory ammo,we are not talking about too much.

Did you do the magic marker test?If your bolt locking lugs are not bearing on the majority of the surface area,they are only bearing on a high spot.It might be as simple as a sharp corner.

It may be a small base die is the answer. I can only see that as true if the problem is a diameter.Small base dies reduce diameter a bit more. OK. IMO,that is related to the chamber.That is where the diameters are.
I don't see how changing the bolt head would bring up the problem of diameter. Length,maybe. How will small base dies help?

Generally,a Gunsmith will have a lathe. See if he will take a shellholder and a carbide tool and face .005 off of a shellholder.. With one of the buzzy engraver pencils,,mark it "-.005" Keep that one in the die box.

 

[Unclenick]

Deck lowering or borrowing a 30-06 pull-through reamer from a Garand rebarreler to fix the chamber.

 

[tangolima]

The gunsmith suggested a small base die. The difference is close to .004". I figured a shell hold would be cheaper. The gunsmith said i will save money by not wearing out brass as fast and taking my barrel out will give me cockeyed sights. As it was it would close on factory with some feel but not much.

A small base die can size a brass shorter? It sizes the brass to a smaller diameter near the head to aid chambering in tight chambers.

-TL

Sent from my SM-G930T using Tapatalk

 

[F. Guffey]

The gunsmith suggested a small base die. The difference is close to .004".

.001" what? And then there is that thing with the head of the case, normal case head expansion on a new, over the counter factory round would be .00025", .004" would be the equivalent of firing the case 16 times. And now back to: Does anyone measure before and again after? I have BAR dies, I have small base dies and I have dies that are mistakes. The difference between a good sizing die and a small base die is not .004", .004" is a mistake. There was a time when I would ask if there are any reloaders that measure case head thickness, I am it. It is tuff to size a case head. And then we need to determine what the smith was talking about when he said there was .004" difference; .004" difference could be the difference in length between a minimum length sized case and a go-gage length case. If the case is in the 30/06 family of cases the differences would be .005", that would be the same differences between the two steps on the Wilson case gage.

F. Guffey

 

[F. Guffey]

The old feeler gage: By placing the feeler gage between the deck of the shell holder and case head the reloader is shortening the case between the datum/shoulder to the case head, at the same time the case diameter is being reduced in diameter in the area of the case web between the case body and case head.

And at the same time it gets more complicated because adding the feeler gage increases the presses ability to over come the cases' ability to resist sizing; again, who measures.

F. Guffey

 

[Yosemite Steve]

.004" is how much more forward the new face is from the old. With it installed the bolt closes with a bit of tension on a factory round as well as on a full sized case.

 

[Yosemite Steve]

I will be picking it up today and see what next I guess.

 

[F. Guffey]

.004" is how much more forward the new face is from the old.

You have a short chamber, basically your chamber is the same length as a minimum length/full length sized case from the datum/shoulder to the bolt face. For me? Not a problem, I have short chambers and I have long chambers. For most it is more than most want to keep up with.

I have 64 chamber reamers and access to 250 more, increasing the length of the chamber .004" from the shoulder to the bolt face should not be difficult. If I was replacing the front of the bolt I would first determine if there were options. But first: I would have determine the length of the chamber before starting/ordering parts.

There was a time when there was a funny story going around about ordering a bucket of bolts, purchasing a bucket of bolts increased the chance of finding the correct bolt. And I asked why? It seems there was no one that could determine how much a bolt off set the length of the chamber.

A friend had a chamber that was .0075" longer than a minimum length chamber or .0025" longer than a go-gage length chamber. He had 100+ bolts, I had 35, I offered to measure all of them in an effort to shorten his chamber but promised him we would be wasting out time.

F. Guffey

 

[Yosemite Steve]

Well, I didn't know any better when I ordered the part. It was a factory bolt head. Then when it came I reallized it was a later model and ordered a new firing pin to fit. But it needed an alignment slot to fit my bolt as well. Running the barrel out looked rediculous. So, it will be reamed or I will try altering the shell holder with the use of a feeler gauge as discussed. I think it would be very cool if it makes the full length sized case a perfect fit. We shall see.

 

[Yosemite Steve]

The old shell holder had a bevel.

Welp. Got my gun back and discovered that I brought the wrong shell holder with me. We turned down my 30-30 shell holder LOL! The only difference I see is that the 30-30 has a thicker (and wider) rim. I think I will make a batch of rounds and see how it works. Now I need to buy another 30-30 shell holder though. Oops!

So the new chamber length is .010" shorter. The barrel has some pitting after cleaning 30 years of copper out of it. I guess I will see how it shoots... I'm back to square one though. I need to find my new sweet spots. I highly doubt that it will still play the same tune it did before. I hope it shoots better.

Updated...As I was measuring my old shell holder I discovered that it was thicker at the back by .004" than the sides. All this time I thought my gun was the culprit for my "not plumb" case heads. As I would measure case length they would always be longer on one side. Nice to have that fixed! On this shell holder I only had the shave it down .006" to get the bolt to close with no feel. 50 rounds sized, trimmed and chamferred now waiting in line to get in the tumbler.