Creating a dummy round?

[MikeMcCasland]

Gents,

I'm about to have a rifle rebarreled again, and the reamer I purchased previously has too short of a freebore. It's a .260 setup with .095 freebore and I should probably be out in the .140 territory to better shoot the heavies.

I don't intend to buy another reamer; I'd rather just have the smith use my existing reamer and throat it longer....unless there's something inherently stupid about doing this vs buying a new reamer?

That said, I took bullet OAL-to-lands readings from the chamber when it was originally cut. I was thinking as far as dummy rounds go, I'd want to just seat my bullets to that reading + 45 thousandths?

Does that sound about right?

 

[Dusty Stevens]

Gents,

I'm about to have a rifle rebarreled again, and the reamer I purchased previously has too short of a freebore. It's a .260 setup with .095 freebore and I should probably be out in the .140 territory to better shoot the heavies.

I don't intend to buy another reamer; I'd rather just have the smith use my existing reamer and throat it longer....unless there's something inherently stupid about doing this vs buying a new reamer?

That said, I took bullet OAL-to-lands readings from the chamber when it was originally cut. I was thinking as far as dummy rounds go, I'd want to just seat my bullets to that reading + 45 thousandths?

Does that sound about right?

Yes or just seat the pressure ring above the potential donut area and send it

 

[Riesel]

Will it still fit in the magazine? Do you plan to shoot using the mag or single shot if necessary? Might end up with feeding problems.

 

[MikeMcCasland]

Will it still fit in the magazine? Do you plan to shoot using the mag or single shot if necessary? Might end up with feeding problems.

It's built on a long action 700. I won't be hitting a mag length problem anytime soon.

 

[6.5 Rooster]

Couldn’t you simply ask your smithy to run a throating reamer in to give you the length you want?

 

[Riesel]

It's built on a long action 700. I won't be hitting a mag length problem anytime soon.

Gotta tell you, didn't see that one coming. IMHO, using that long action is really going to give that .260 a chance to shine.

 

[MikeMcCasland]

Couldn’t you simply ask your smithy to run a throating reamer in to give you the length you want?

Yep. That's exactly what I'm asking. To put it more simply "How should I determine the length of a dummy round?"

Do I just arbitrarily seat a heavier bullet out past the donut, or should I seat it to match a known reamer freebore?

 

[#40Fan]

I'd seat the bullet above the possible donut area and then give yourself whatever you think you might be jumping the bullet at, plus a few thousandths for different bullets.

 

[Dusty Stevens]

Do I just arbitrarily seat a heavier bullet out past the donut?

Yes. Theres no way to reliably seat one and say what freebore it is. You get a .125fb reamer from 3mfrs and then get them again 6mo later and none of them will be the same. Ive sent in the same exact dummy round and got different fb measurements too so just seat it where you want it and send r in

 

[MikeMcCasland]

Yes. Theres no way to reliably seat one and say what freebore it is. You get a .125fb reamer from 3mfrs and then get them again 6mo later and none of them will be the same. Ive sent in the same exact dummy round and got different fb measurements too so just seat it where you want it and send r in

Sounds good Dusty. I'll just handle it that way.

Thanks!

 

[Pwc]

What is yhe purpose of the dummy round? Dry fire practice, doesn't need to be crush fift on lands. Flill primer cup with r RTV. No matter what "they" say steel on steel does stress the firing mechanism, and will eventually break.

 

[MikeMcCasland]

What is yhe purpose of the dummy round? Dry fire practice, doesn't need to be crush fift on lands. Flill primer cup with r RTV. No matter what "they" say steel on steel does stress the firing mechanism, and will eventually break.

The purpose is to throat the chamber longer than my reamer is cut for; it gives a few benefits. First you have it throated for a specific bullet, and secondly, you can set it up so that bullet is seated far out within the neck, giving you additional powder capacity, and avoiding any interference from the shoulder/neck donut area.

 

[Pwc]

I would guess the bullet needs to be hard crimped or even soldered to keep it from moving, if it is to be used as a gage.

 

[10at6]

I would guess the bullet needs to be hard crimped or even soldered to keep it from moving, if it is to be used as a gage.

I always solder my bullets to keep them from moving.. It's hard and takes a lot of time.

 

[Dusty Stevens]

I always solder my bullets to keep them from moving.. It's hard and takes a lot of time.

I solder mine for more neck tension