Gunsmithing Chamber throat too short.

[pinzmann]

I goofed on chambering a rifle and now my throat is too short. I need more freebore for the VLD bullets that I want to load. Is there a safe way to open up the throat. I notice that PT&G has a throat reamer but have heard that this is not a good idea. What other options do I have if any.

 

[Aeon1]

Nothing wrong or hard about using a throating reamer. I have PTG uni-throaters for almost every caliber and nothing hard about using them. I have several reamers with minimum freebore so I can move throats out as needed with a throating reamer. They take some care to use but it's not hard. Uni-throaters can be used on a barreled action too. I make up a nylon guide bushing at the back of the action to guide the t handle. Standard uni-throaters are usually .0005" over nominal bullet dia and 1°-30 but PTG can grind any dimension.

 

[pinzmann]

Will changing the throat have any effect on the accuracy nodes? In other words will I have to adjust my load?

 

[buffybuster]

Will changing the throat have any effect on the accuracy nodes? In other words will I have to adjust my load?

Very possibly you will have to do some load redevelopment, depending on how far you extend the throat, as you will be increasing the case volume, which will alter the pressure curve.

 

[SSC]

Yea it will affect your load. Can't say if it won't be accurate still it not but it will for sure change. The more you move the throat the more case volume you are creating.

 

[jsthntn247]

Yes, you will be able to reach a higher node (more powder room for same pressure) and get more velocity. Make a dummy round at the length you want and throat it out until you get land marks on the dummy round.

 

[dieselten]

Does the PTG unithroater come with a pre installed pilot? Or do I pick the size I want when I order it? I have a Kreiger .243 barrel, any recomendation on the pilot?

Thanks

 

[beanland]

They do a .236 and a .237. You really need to know what you have. But say you have a .236. I would order a .2358 pilot which will be .0002 smaller for a little clearance. The uni throaters will work fine. Just go slow and check often. It is easy to cut much. Yes you will probably have to retune your load.

 

[Aeon1]

Does the PTG unithroater come with a pre installed pilot? Or do I pick the size I want when I order it? I have a Kreiger .243 barrel, any recomendation on the pilot?

Thanks

Uni-throater's come with one pilot. You can specify what size you want. There are standard sizes PTG can provide ranging in size (for 6mm/.243) from .2352" to .2378" in .0002" increments but they will make you anything you want. Trouble is it's hard to pick just one that's going to fit for sure. Most of us doing this work end up with lots of bushings as barrels vary even within the marked nominal bore dimensions.