How to open a bolt face?

[haeffnkr]

Hi,
I am wanting to open a howa mini bolt up to standard diameter.
Do need a mill or a lathe?
How do I deal with the handle?

thanks in advance!
haeffnkr

 

[DaveTooley]

It's not designed to handle those pressures.

 

[linebaugh]

That bolt cant be opened to standard. PPC is biggest

 

[WSnyder]

Many have done that (STD bolt face) and chambered them for BRA's and the like.

 

[Walt Krafft]

Opening the bolt is easy. Getting an extractor to work may not be.

 

[WSnyder]

It’s just an M-16 style claw extractor. Not much would need to be done to go from PPC to a BR rim. Still with the Grendel and ARC’s readily available now I’m not sure why one would want or really need to go BR.

 

[haeffnkr]

Will the jaws on a lathe go around the bolt do most use a mill to do the work?

 

[ELR LVR]

Will the jaws on a lathe go around the bolt do most use a mill to do the work?

There are a few different methods
the easiest requiring the least amount of extra fixtures and tooling
--- is removing the firing pin and shroud from the rear
screw a threaded blank into the rear of the bolt, then chuck the blank in the lathe
then hold the face end of the bolt with a steady rest
---Go to work
---
one post on here the other day a guy showed a very nice bolt holding fixture he made out of 2-3 inch bar stock or pipe... and bored the center out, then milled a slot for the bolt handle to stick out the side through
then - to align and hold the bolt in the center he used 4 set screws spaced a few inches apart
same as we use the 4 bolt spider to hold the back end of the barrel with when dialing in a barrel in the lathe
---
then there's fixtures you can buy from places like Brownells
this you would clamp your bolt in, and then chuck it in a 4 jaw and center it up

 

[jackieschmidt]

Here is how I opened up my Bat M bolt to accept the 338 Lapua case.

However, it has a screw in shroud. To do a bolt with a Bayonet Style Bolt, I would probably press a piece into the rear cylindrical part of the bolt.

 

[mike mccormick]

Here is how I opened up my Bat M bolt to accept the 338 Lapua case.

However, it has a screw in shroud. To do a bolt with a Bayonet Style Bolt, I would probably press a piece into the rear cylindrical part of the bolt.View attachment 1714064View attachment 1714065View attachment 1714066

Exact same setup that I use. I use it to bush firing pins too

 

[Skattergun]

Another option is in a mill with a boring head, done a bunch that way.

 

[pavementends]

I thought the Howa mini action was the same dia as the standard Howa 1500 including the bolt. It is just shorter. I do not have both here to check.

 

[WSnyder]

I thought the Howa mini action was the same dia as the standard Howa 1500 including the bolt. It is just shorter. I do not have both here to check.

He’s not asking about bolt diameter he’s asking about how to open up the boltface for a larger diameter cartridge.

 

[STS]

It's not designed to handle those pressures.

I'm thinking I would listen to this fellow here ^^^^^^^^.

 

[Ggmac]

Listen to Dave Tooley. If you insist on doing a larger cartridge, I suggest modifying thecase heads instead of the bolt . This way the next owner will not think the action will handle whatever case fits . Case rim modifications are easy and requires you to segregate your cases for this action.

 

[kendog]

It's not designed to handle those pressures.

Hmmm...
The Howa Mini is available in calibers generating some of the standard/highest pressures now. 52 to 58K PSI. 6.5 Grendel and .223 specifically. What would be the difference?

 

[Ggmac]

Hmmm...
The Howa Mini is available in calibers generating some of the standard/highest pressures now. 52 to 58K PSI. 6.5 Grendel and .223 specifically. What would be the difference?

Probably bolt thrust and pressures are , what we usually forget , in PSI , pounds per square inch . I don’t mean to be disrespectful, just that sometimes we only look at one figure nd not the entire picture.
223 has a fairly small footprint compared to ay the 6.5 grendell .
I’m going from memory here so give me some slack if wrong.

 

[WSnyder]

The bolt thrust and hoop strength on the .223 wouldn’t be an issue at all but yeah the Grendel and ARC’s are a good measure of what the action may handle.

 

[DaveTooley]

The bolt thrust and hoop strength on the .223 wouldn’t be an issue at all but yeah the Grendel and ARC’s are a good measure of what the action may handle.

^^^^^^^^^^

 

[kendog]

The bolt thrust and hoop strength on the .223 wouldn’t be an issue at all but yeah the Grendel and ARC’s are a good measure of what the action may handle.

The original comment was regarding pressure. Grendel pressure is right up there with the BR's. Does the larger diameter (.473") change things? Just trying to understand whats going on. Thanks