Pacific tool uni throater necker kit sizing .30

[PakProtector]

I have a tool grinding company that modifies reamers to print. I just got a straight flute reamer modified with a 10-degree included angle for a .25 pellet barrel. It cut brilliantly, and cost me a week wait, and $46. Going to get another for my next barrel, a slow twist .300 pellet barrel from TJ's. I expect that reamer blank to be slightly more. Going to try a helical twist flute blank this time. I had them leave me a .125 stub up front for fitting a PEEK. Going to try a grooved one next time and make the pilot bushing from steel, custom fit for the barrel in hand.
cheers,
Douglas

[mackeral5]

I have a tool grinding company that modifies reamers to print. I just got a straight flute reamer modified with a 10-degree included angle for a .25 pellet barrel. It cut brilliantly, and cost me a week wait, and $46. Going to get another for my next barrel, a slow twist .300 pellet barrel from TJ's. I expect that reamer blank to be slightly more. Going to try a helical twist flute blank this time. I had them leave me a .125 stub up front for fitting a PEEK. Going to try a grooved one next time and make the pilot bushing from steel, custom fit for the barrel in hand.
cheers,
Douglas

That sounds great, your previous posts about using a local tool grinder persuaded me to slow down this pursuit a bit and see what other options are available.  I recently ordered a #7 taper pin reamer, with hopes of modifying it to create a  lead on a .357 barrel that should arrive from TJ's this Friday. I ordered 30" of barrel, if I fail at DIY I can just cut off my failure and farm out the work, with a goal of maintaining 28" minimum barrel length.

[Sbak]

I might get blasted for saying this, but in my experience with airgun barrels having a lead is crucial for accuracy when shooting bullets. However, the precision of the lead matters little. I've used sand paper and a couple of dowels with a good bit of patience to produce a number of great shooting barrels. Sand the throat out completely, and the dowel/sand paper will cut a taper whether you want it to or not.

[mackeral5]

I ended up modifying a #7 taper pin reamer, loosely following the method Douglas described.  This was for a .357 TJ's 1:26 barrel, not the barrels that were the subject of this thread.  I will modify those barrels using the same method at a later date.

I say loosely followed Douglas' instructions because I didn't take any measurements.  I simply ran it into the raw bore until it was deep enough that it opened the chamber end up to the point where the base of a .358 slug would just fit.  Then marked the reamer and reduced the diameter beyond the mark, towards the big end.  Once a couple of inches were reduced to .345 or so I was finished.
Then I ran it into the bore slowly, frequently retracting and clearing chips.  When clearing chips I would test fit an NSA 105gr.  Once it was engaging rifling when seated just beyond the transfer port I was finished.  I basically cut the chamber and lead all in one series of operations with the same tool.  Then I finished lapping the breech end of the barrel. 

It worked pretty well, at least from the looks of the lead and how it feels when slugging the barrel.  It will be some time before I can do any accuracy testing.  I was comfortable enough doing it that I ordered #2, #4, #5, #6 to use for making .177-.30 tools.   

[rsterne]

Tapered Pin Reamers are 1/4" per foot, which works out to 1.2 deg. included angle.... which should work out great....

Bob

[Insanity]

Would a #5 ream be the one for .25/.257? What I think I am seeing is the start would be under sized then the ream would end with a larger size so that I can modify it like Mac described.

[rsterne]

A #5 tapered pin reamer starts at 0.2407" and ends at 0.2994".... A #4 starts at 0.2071" and ends at 0.2600".... Either would work for a .25 cal or .257 cal.... but the #4 could also be used in a .22 cal or .224 cal.... Since you probably would want to grind away the flutes after it reaches chamber diameter you would need two anyways.... A #3 will also work for .22 cal or .224 cal, it starts at 0.1813" and ends at 0.2294".... A #2 would be the size for .177 cal, it starts at 0.1605" and ends at 0.2010".... A #6 would work for .30 cal or .308 cal, it starts at 0.2773" and ends at 0.354".... As mentioned above, the #7 is for .35 and .357 cal....

Bob

[Bob Pratl]

A #5 tapered pin reamer starts at 0.2407" and ends at 0.2994".... A #4 starts at 0.2071" and ends at 0.2600".... Either would work for a .25 cal or .257 cal.... but the #4 could also be used in a .22 cal or .224 cal.... Since you probably would want to grind away the flutes after it reaches chamber diameter you would need two anyways.... A #3 will also work for .22 cal or .224 cal, it starts at 0.1813" and ends at 0.2294".... A #2 would be the size for .177 cal, it starts at 0.1605" and ends at 0.2010".... A #6 would work for .30 cal or .308 cal, it starts at 0.2773" and ends at 0.354".... As mentioned above, the #7 is for .35 and .357 cal....
Bob

Bob, thanks for this information, I just order a #4.

[rsterne]

Let us know what mods you did to it, and how it works....

Bob

[HunterWhite]

Be careful when you order.  There are #4 reamers, and there are 4/0 reamers. Very different.  I don't know why.

Maybe this:


I don't see the whole specifications so please verify the size.
Hunter

[rsterne]

I believe a # 4/0 reamer is a # 0000 (called a "four ought" ).... ie a lot smaller than a # 0.... You want a # 4....

Bob

[Bob Pratl]

Be careful when you order.  There are #4 reamers, and there are 4/0 reamers. Very different.  I don't know why.
Maybe this:

I don't see the whole specifications so please verify the size.
Hunter

Hunter,Good point, I did notice the same thing and I ordered the #4 and not the #4/0.

[Bob Pratl]

Let us know what mods you did to it, and how it works....
Bob

The first one that I plan to do with it is the .22 Liberty which has a large step, as seem with a bore scope, that is excessive with an undersized bore (.214"). If it works out I will check out my other toys and order the appropriate reamer. It always bother me but I did not want to spend $50 for the proper reamer and I almost got in there with Dremel mounted in a lathe. I think that the reamer will work out OK. Good find...thanks.

[HunterWhite]

I don't know which one you ordered,  but I chose the spiral fluted one. The one that I have is no longer available. 
The spiral is to the left, but the cutting edge is to the right.  This prevents it from pulling itself into the work. It cuts clockwise just like a regular drill. When you reverse the tool it clears the chips.
I chose the spiral flutes because I thought that a straight flute would chatter on the rifling.
Please note that I am NOT a machinist.

Hunter

[Bob Pratl]

I don't know which one you ordered,  but I chose the spiral fluted one. The one that I have is no longer available. 
The spiral is to the left, but the cutting edge is to the right.  This prevents it from pulling itself into the work. It cuts clockwise just like a regular drill. When you reverse the tool it clears the chips.
I chose the spiral flutes because I thought that a straight flute would chatter on the rifling.
Please note that I am NOT a machinist.
Hunter

Hunter, I also ordered the spiral reamer. I was told many years ago that you should never turn a reamer in the reverse direction as it will dull it.
I don't know now true it is but I followed his directions.

[HunterWhite]

Yes, if all else fails, follow the directions.
I never reversed it, it was in the description of the one that I bought.
The amount of chips is very small. Most of the chips stay in the reamer and cutting oil.
It does push the chips into the breech. Clean it well.

Hunter