Question on Cone Cutter for BAT

[gunsandgunsmithing]

Mike, The vipers where coned at least mine was. they changed when the drop port came around....

Yes, he offered them two or three different ways..some with a rem style breech, some fully coned and some like mine was. I just don't recall a 29°, but maybe he did.

He use to keep all his tenon drawings on his site but they appear to be gone since he sold out.

Oh, fwiw..I don't think he ever offered a flat breech but I've seen them cut that way, with a coned bolt. Had one come into my shop that way. Had to check it over and IIRC, it was supposed to have a tenon like mine, so I did it right when I bbl'd it. The end clearance was good but no cone on the breech to match the bolt. Probably ok from a safety standpoint but I think he added the 14° cone to aid feeding a bit.

 

[Lucky Shooter]

Mke, the old Viper drawings seem to be gone and I still have one of the actions,
not a drop port.

An old paper copy shows a 29 degree cone, tenon length of 1.115" and 1.0625-18 TPI.

Have never heard it mentioned but would expect barrels could be interchanged between
these Stiller Vipers and Panda's.

 

[gunsandgunsmithing]

Mke, the old Viper drawings seem to be gone and I still have one of the actions,
not a drop port.

An old paper copy shows a 29 degree cone, tenon length of 1.115" and 1.0625-18 TPI.

Have never heard it mentioned but would expect barrels could be interchanged between
these Stiller Vipers and Panda's.

Then 29 it is. I had printed those out too but didn't see the need...until I needed them and they were gone from his site.

 

[gunsandgunsmithing]

Found these two but not the print for the full coned breech. These have seen better days.

 

[geo.ulrich]

yep the top one says drop ports. 2nd is for predator action...

 

[gunsandgunsmithing]

yep the top one says drop ports. 2nd is for predator action...

More to it...he had prefix "a", "b" and "c' actions, denoted by the first digit of the serial number. Mine was a B

 

[geo.ulrich]

I don't remember #on mine, funny different model is not designated on drawing.... I seem to recall some were a standard remington nose configuration but I am probably remebering wrong... I do recall feeding was an issue with the drop ports, enough so some took to grinding a small lead at 6 o'clock on chamber...

 

[gunsandgunsmithing]

I don't remember #on mine, funny different model is not designated on drawing.... I seem to recall some were a standard remington nose configuration but I am probably remebering wrong... I do recall feeding was an issue with the drop ports, enough so some took to grinding a small lead at 6 o'clock on chamber...

My breech was like the top pic. It fed really well. I remember just a time or so having the bullet tip hit the flat around the chamber when I was trying to run fast, above my skill level. And it was a 30 on a Grendel, so smaller diametrically than say a BR. I loved that gun and have regretted selling it at times.

Oh, and I remember seeing the abc designation on a print or at least in print somewhere. Actually, I think there were just b, c and no designation on the first series.

 

[geo.ulrich]

. I loved that gun and have regretted selling it at times.

I thought mine was real good also but it was a rb,lp which is opposite of what I needed...

 

[hoz53]

My point was how fast actual bolt clearance and the amount of unsupported case can change with simply being off a small amount on the compound. Dusty brought up a good point in that the scale on the lathe compound can very well be off to some degree.

I use an indicator set up axially with the chuck or work piece to set it accurately. I simply put the indicator tip against the tool holder or post and move the compound exactly 1.000". I adjust until the indicator agrees with the sine of the angle in the link I just posted above.

JMHO, but I'd err to the side of the cone of the bbl being a tad too flat as opposed to too steep but if you set the compound like I just described, you don't have to worry about it..it's right.

Im glad you brought up the differance to begin with. Setting the angle like you say here is what i was looking for in all this as and like everything there is more than one way to do it. I just gotta figure it out-- Thanks. More questions will probably follow

 

[hoz53]

Got my trig functions messed up. Should be sine(1°) which is indeed 0.0175. cosine is adjacent over hypotenuse which would mean that with a hypotenuse of 1 inch, the adjacent would be 0.99985. The opposite is the sine and would be 0.0175.

you can use different trig functions and they all get you to same place for sure. I used Tan 1degree= opp/adj--- substitute 1" for adjacent so
Tan1deg= opp/1 multiply through by 1 and you get Tan1deg=opposite
Tan 1deg=.017 something---I did it the hard way didnt I

 

[hoz53]

Let me ask it this way. Why would PTG make a tool called the "64 Degree BAT Breech Tool" when BAT says it's cones are 65 degrees?

Let me ask it this way. Why would PTG make a tool called the "64 Degree BAT Breech Tool" when BAT says it's cones are 65 degrees?

Thanks getting this thread started INTJ- alot of good info resulted from some very knowledgeable people.

 

[INTJ]

Likely a good question for PTG. It may be correct or may be as simple as a typo. I pulled it up on their site and zoomed in on the pic of the tool itself. The one in the pic is marked 65° BAT but the desription say 64°. I dunno.

You are right--it does say 65 degrees on the actual reamer. They just made a mistake on the website listing.

BTW, yesterday PTG couldn't answer my question......

 

[hoz53]

You are right--it does say 65 degrees on the actual reamer. They just made a mistake on the website listing.

BTW, yesterday PTG couldn't answer my question......

I have a Rem700 with a Coned bolt I got from PTG (whole action with coned bolt). I checked the bolt today with a protractor at it showed 32.5 degrees from what I could see. of coarse my technique and instrument were not the most precise. Just wondering how it compares with others.

 

[INTJ]

I have a Rem700 with a Coned bolt I got from PTG (whole action with coned bolt). I checked the bolt today with a protractor at it showed 32.5 degrees from what I could see. of coarse my technique and instrument were not the most precise. Just wondering how it compares with others.

A 32.5 Cone would require a 57.5 degree cutter.

 

[wwbrown]

Got my trig functions messed up. Should be sine(1°) which is indeed 0.0175. cosine is adjacent over hypotenuse which would mean that with a hypotenuse of 1 inch, the adjacent would be 0.99985. The opposite is the sine and would be 0.0175.

Since your are comparing the geometry of cones of 65° and 64° you need to compare the trig functions using those two angles. Yes there is a difference of 1° but trig functions are not linear so in cases like this you need to comapre the trig functions of the actual angles and not the difference.

Example:
sin(1°) = 0.01745
sin(65°) - sin(64°) = 0.00751

 

[GenePoole]

Since your are comparing the geometry of cones of 65° and 64° you need to compare the trig functions using those two angles. Yes there is a difference of 1° but trig functions are not linear so in cases like this you need to comapre the trig functions of the actual angles and not the difference.

Example:
sin(1°) = 0.01745
sin(65°) - sin(64°) = 0.00751

While your equations are true, they are apples and oranges. The second one is essentially the difference in height of two triangles with those angles (and equal hypotenuses). That would be the difference in o1 and o2 below:

 

[INTJ]

Fortunately, none of the math matters because the PTG BAT Breech Tool is just mismarked on the website. It's really 65 a degree tool.

 

[Keith Hansley in NC]

how do you know if the pic is right for the description
may be just a generic pic and what you will get if ordered is truly a 64 deg. cutter
look at other pics on PTG website, many are generic

 

[GenePoole]

It says right in the description (misspelling of "receive" is theirs):

"The image used is for representation purposes only. The item you recieve may differ in appearance."