PTG Unithroater - straight or spiral flutes?

[Shinbone]

I bought a used Ruger Hawkeye in .223Rem at Cabelas. The rifle is in really good condition. Looks like it has hardly been shot.

Got it home and ran a borescope through it. I am very impressed with how smooth the Ruger barrel is! Probably the smoothest factory barrel I have ever seen.

However, the chamber has zero freebore. As in zip, nada, nothing, 0.000".



No problem. Now I have an excuse to buy a Unithroater kit. My plan is to hand ream about 0.025" of freebore with the barrel on the action. I've got other rifles that I will eventually want to use the Unithroater on, as well.

I see the Unithroater reamer comes with either straight flutes or spiral flutes. What are the benefits of each flute design and which would be best for my application?

 

[Roeder]

I bought a used Ruger Hawkeye in .223Rem at Cabelas. The rifle is in really good condition. Looks like it has hardly been shot.

Got it home and ran a borescope through it. I am very impressed with how smooth the Ruger barrel is! Probably the smoothest factory barrel I have ever seen.

However, the chamber has zero freebore. As in zip, nada, nothing, 0.000".



No problem. Now I have an excuse to buy a Unithroater kit. My plan is to hand ream about 0.025" of freebore with the barrel on the action. I've got other rifles that I will eventually want to use the Unithroater on, as well.

I see the Unithroater reamer comes with either straight flutes or spiral flutes. What are the benefits of each flute design and which would be best for my application?

The spiral flutes are much easier to use by hand as they don't tend to catch on the lands. They also tend to leave a smoother finish. Even if the spiral flute is a bit more expensive and requires a wait, it is worth it. Incidentally, the zero freebore chamber is intended for 40 and 50 grain projectiles and usually goes with a 14 twist. Heavier bullets don't shoot in those at all.

 

[Shinbone]

Thanks for the info, both on the flutes and the freebore. Looks like I need to do some more research on .223Rem freebore numbers before pulling the trigger on anything.

 

[Dusty Stevens]

The freebore is set up for the bullet its intended to shoot with its twist rate. Extending the freebore will just make it too long

 

[clowdis]

The Ruger Hawkeye predator lists the barrel twist at 9". Good for up to 75gr. bullets maybe. https://ruger.com/products/HawkeyePredator/specSheets/17122.html

 

[Ggmac]

I bought a used Ruger Hawkeye in .223Rem at Cabelas. The rifle is in really good condition. Looks like it has hardly been shot.

Got it home and ran a borescope through it. I am very impressed with how smooth the Ruger barrel is! Probably the smoothest factory barrel I have ever seen.

However, the chamber has zero freebore. As in zip, nada, nothing, 0.000".



No problem. Now I have an excuse to buy a Unithroater kit. My plan is to hand ream about 0.025" of freebore with the barrel on the action. I've got other rifles that I will eventually want to use the Unithroater on, as well.

I see the Unithroater reamer comes with either straight flutes or spiral flutes. What are the benefits of each flute design and which would be best for my application?

The picture you posted can't tell how much freebore exists , or at least its deceiving. You need to first establish the chamber case/neck length , then figure out the angle and rifling depth .
It does look short but a chamber cast will tell.
Have you tried to chamber bullets in cases made to different lengths ?

 

[gunsandgunsmithing]

Often, the benefit of a spiral flute is for the spiral to be left handed, so as to not "pull" the reamer in

The picture you posted can't tell how much freebore exists , or at least its deceiving. You need to first establish the chamber case/neck length , then figure out the angle and rifling depth .
It does look short but a chamber cast will tell.
Have you tried to chamber bullets in cases made to different lengths ?

Agreed. Actually, it looks to me to have about .025-.030ish of actual freebore. but it's hard to say from a pic. You can see some area that is machined away in the right area, to be called freebore. "effective freebore is impossible to determine from the pic, being from the end of the case mouth to the end of the actual chamber plus any freebore.

 

[Ggmac]

Often, the benefit of a spiral flute is for the spiral to be left handed, so as to not "pull" the reamer in

Agreed. Actually, it looks to me to have about .025-.030ish of actual freebore. but it's hard to say from a pic. You can see some area that is machined away in the right area, to be called freebore. "effective freebore is impossible to determine from the pic, being from the end of the case mouth to the end of the actual chamber plus any freebore.

I've seen some manufacturers, ones that use un piloted reamers , use longer than spec necks and count that as part of the ball seat / freebore . I guess it counts , not in the aftermarket custom world but . Also bore diam and groove dia would skew a picture.

 

[carlsbad]

Factory barrels with not enough freebore is an unusual problem.

 

[Dusty Stevens]

Factory barrels with not enough freebore is an unusual problem.

I usually see it 99% of the time on a mag fed 223

 

[46and2]

I've seen some manufacturers, ones that use un piloted reamers , use longer than spec necks and count that as part of the ball seat / freebore . I guess it counts , not in the aftermarket custom world but . Also bore diam and groove dia would skew a picture.

I received a barrel with a stupid long neck and 0.0 freebore...so freaking retarded. I'm just about to send it back!
When Weatherby chambers have .375 freebore the diameter is only less than .001" larger than caliber... NOT .038" !!!

 

[Ggmac]

I received a barrel with a stupid long neck and 0.0 freebore...so freaking retarded. I'm just about to send it back!
When Weatherby chambers have .375 freebore the diameter is only less than .001" larger than caliber... NOT .038" !!!

Is it the Weatherby your talking about ? Is it a factory Weatherby ? That wasn't the manufacturer I was talking about but I would believe it .
So your neck is only .005 larger than the freebore of a print ?

 

[46and2]

Is it the Weatherby your talking about ? Is it a factory Weatherby ? That wasn't the manufacturer I was talking about but I would believe it .
So your neck is only .005 larger than the freebore of a print ?

No. The retard barrel is not a Weatherby chamber, nor chambered by Weatherby.

I just used Weatherby as an example of a unique but effective chamber design. The bullet has a ton of freebore but the freebore is tight so the bullet can stay aligned with the bore center line when it slams into the lands.
The chamber I received has a .600" long area of slop! About .340" diameter for a .264" bullet.

 

[Ggmac]

No. The retard barrel is not a Weatherby chamber, nor chambered by Weatherby.

I just used Weatherby as an example of a unique but effective chamber design. The bullet has a ton of freebore but the freebore is tight so the bullet can stay aligned with the bore center line when it slams into the lands.
The chamber I received has a .600" long area of slop! About .340" diameter for a .264" bullet.

I've seen it done a lot .