Education and Confirmation Time Re: Reamer Specs Related to 'Freebore'

[6and7mm]

Folks, help me settle a small debate...

Note the reamer drawing attached herein.

Note specifically the two dimensions listed as 1) LEAD, and 2) THROAT.

Question 1:
Which of these two terms listed above actually reference FREE BORE?

Once I receive quality answers from the group, I will post part two of my questions. Thanks in advance for qualified input. Please do not answer with your speculation. I am seeking confirmation based on authority of the subject

 

[DaveTooley]

Freebore = lead in this drawing. Diameter and length are the only numbers involved.
Throat is the overall length from the neck to a predetermined bore diameter to include freebore and the lead angle.

Now most, if not all us consider freebore as the cylinder section follwed by the lead which can have different angles. Different angles can change the intersection point of the bullet and the rifling.

 

[6and7mm]

Thank you, Dave.

Next questions are:

Based on the original reamer drawing provided in the original post...

Question 2:
Is the LEAD the .114" call-out dimension?

Question 3:
In regards to trying to get the bullets to just touch the lands AND have an appropriate amount of the bullet held into the neck...
Would this reamer be appropriate for 50-60 grain Boattail bullets? I assume it is not best for 40 grain varmint bullets. Correct?

 

[NorCalMikie]

From my experience, 40 grain bullets are shorter so, the base will seat at the shoulder neck junction and not into the powder.
Longer (heavier) bullets will be into the powder if you run a ZERO freebore.
ZERO freebore will allow you to use the lightest (shortest) bullets you can get your hands on, seat them at or into the lands and and allow you to go heavier as the throat wears and still be close or at the lands. Works for me.
I have found that bullets seated with a jump to the lands will show pressure at a given powder charge but that "same exact charge" with the bullets set at a jam won't show pressure and ever allow you to higher in charge with no ill effects. YMMV.

 

[Gb300wm]

Freebore is 0.100”

 

[6and7mm]

From my experience, 40 grain bullets are shorter so, the base will seat at the shoulder neck junction and not into the powder.
Longer (heavier) bullets will be into the powder if you run a ZERO freebore.
ZERO freebore will allow you to use the lightest (shortest) bullets you can get your hands on, seat them at or into the lands and and allow you to go heavier as the throat wears and still be close or at the lands. Works for me.
I have found that bullets seated with a jump to the lands will show pressure at a given powder charge but that "same exact charge" with the bullets set at a jam won't show pressure and ever allow you to higher in charge with no ill effects. YMMV.

Understood re: your suggested 'zero' freebore/lead. I have this reamer as in the print, and am wanting to double check a few things before I start chambering barrels.

I want to ensure that I can get 50 and 55 grain boattail bullets to just kiss the lands, be into the neck for a good tight bullet hold in the case neck for field use, and then not be below the neck shoulder junction (the latter is not much of a concern with these lighter weight bullets).
Thanks.

 

[6and7mm]

Freebore is 0.100”

Thank you.

Do you agree with the following:
If 0.100" is the free bore, then 40 grain boolits are not likely a good choice for what I want this chamber reamer to accomplish. However, it does seem like 50 or 55 grain boattail boolits would be able to be seated into the case necks, kiss the rifling when properly seated, and avoid the neck and shoulder junction.

It also seems like the reamer would work well for 70-80 grain boolits -- assuming the barrel twist is appropriate.

 

[BoydAllen]

Assuming that you plan on cutting the blank to a specific length you can set it up, so that you are working on the part that will later be cut off, or if you have already done that use the cut off piece to cut a partial chamber, including the shoulder, and do your dummy round testing with that.

 

[Evan]

I used this exact same reamer.

http://forum.accurateshooter.com/threads/my-new-22br.3981971/#post-37528808

You can see in the picture in that link that the 88ELD is pretty well suited to this 0.100 freebore. Someone try to squeeze as much capacity out as possible would want a longer freebore, but this one works with the 70-95gn bullets.

This freebore is VERY long for the lighter bullets. You'll have to jump them a ways. I would look for a much shorter freebore to shoot the 40-70gn bullets. Perhaps a 0.040 freebore or so.

If you order your own reamer, I'd increase the neck to a 254 for a tiny bit more breathing room and I'd change the OAL from 1.555 to 1.565 so that you can neck down 6BR brass and not need to trim much at all. The 1.555 OAL requires about 0.010 of trimming, if I recall correctly (it's been a year since I prepped the brass I'm currently using).

 

[6and7mm]

Assuming that you plan on cutting the blank to a specific length you can set it up, so that you are working on the part that will later be cut off, or if you have already done that use the cut off piece to cut a partial chamber, including the shoulder, and do your dummy round testing with that.

Thanks, Boyd. I understand that option.

It seems like a relevant need in this community is a software program that allows you to input the chamber reamer specs from shoulder forward, input the bullet brand, caliber, weight via bullet part number, and have the software show the overlay of the reamer cut and bullet overlay -- allowing the the user to select bullet placement in the neck area and lands area -- then one could proactively better assess their bullet selection and options to save time, grief, money, and gunsmithing resources.

There is still more trial and error than is necessary with today's technology. I appreciate the answers and feedback. Keep it coming with relevant input.

 

[6and7mm]

I used this exact same reamer.

http://forum.accurateshooter.com/threads/my-new-22br.3981971/#post-37528808

You can see in the picture in that link that the 88ELD is pretty well suited to this 0.100 freebore. Someone try to squeeze as much capacity out as possible would want a longer freebore, but this one works with the 70-95gn bullets.

This freebore is VERY long for the lighter bullets. You'll have to jump them a ways. I would look for a much shorter freebore to shoot the 40-70gn bullets. Perhaps a 0.040 freebore or so.

If you order your own reamer, I'd increase the neck to a 254 for a tiny bit more breathing room and I'd change the OAL from 1.555 to 1.565 so that you can neck down 6BR brass and not need to trim much at all. The 1.555 OAL requires about 0.010 of trimming, if I recall correctly (it's been a year since I prepped the brass I'm currently using).

Thank you. This is the type of input I am seeking with relevant commentary based on real world application.

I DON'T have a desire to sling heavy bullets from a 22 BR, but rather 50-70 grain options primarily for varmint and shorter range target shooting. My 6 BRs and Dashers can tackle the heavier bullets at greater distances.

I appreciate the replies.

 

[Evan]

Here's what I've got on hand: Top - 40gn Sierra Blitzking, 50 VMAX, 55 VMAX, 69 Sierra Matchking, 80 ELD, 90 Berger VLD, 88 ELD, and 95 Sierra Matchking. Loaded rounds top and bottom are 88ELDs at a 0.010" jump to the lands. As you can see, with this freebore you wouldn't be able to load the 40-69 without a pretty decent jump, and even then you'd only have the smallest amount of neck to hold the bullet.

 

[6and7mm]

View attachment 1189518
Here's what I've got on hand: Top - 40gn Sierra Blitzking, 50 VMAX, 55 VMAX, 69 Sierra Matchking, 80 ELD, 90 Berger VLD, 88 ELD, and 95 Sierra Matchking. Loaded rounds top and bottom are 88ELDs at a 0.010" jump to the lands. As you can see, with this freebore you wouldn't be able to load the 40-69 without a pretty decent jump, and even then you'd only have the smallest amount of neck to hold the bullet.

Yes, that makes sense. Basically, the reamer is for heavier 22 caliber bullets for more ideal bullet seating arrangements. It is TOUGH to locate a good spec'd 22 BR reamer, no-turn, no trim, for Lapua brass, with live pilot, at the ready to purchase. Let me know if you know of one.

Thank you for the commentary.

 

[Gb300wm]

I think you have your answers above. From what I understand that you may want, a 0.000” freebore would work just fine with bullets up to 70 grains or so. The 22br does have a fairly long neck....
this reamer is probably cut for the longer 90 gr f-class projectiles.

 

[NorCalMikie]

And you have to remember, most reamers are cut about .020 "longer" than the listed Max trim length. So double check your case lengths BEFORE you start trimming. You may not need to trim for a looong time.

 

[BoydAllen]

If you have one "gizzy" of known throat angle and freebore length for the caliber that you are interested in, and a suitable matching (matching the gizzy) case, you can use it to see where any bullet would be in that case, and with a little math what freebore would be required to have a bullet your preferred distance into any case.

 

[Evan]

If it will be useful to anyone, I'm happy to take the time and measure a few of the bullets I have and give real numbers on how they will fit to go with the quick photo I put together above. That way you can choose the freebore based on how much neck you want gripping the bullet.

Sounds like @6and7mm is looking for an existing reamer though, so any reamer with 0.040" or less freebore will work.

 

[Doug Beach]

Yes, that makes sense. Basically, the reamer is for heavier 22 caliber bullets for more ideal bullet seating arrangements. It is TOUGH to locate a good spec'd 22 BR reamer, no-turn, no trim, for Lapua brass, with live pilot, at the ready to purchase. Let me know if you know of one.

Thank you for the commentary.

The sooner you order the reamer you want, the sooner you’ll get it.

 

[Medic505]

The sooner you order the reamer you want, the sooner you’ll get it.

Unless you order from PTG, then you have about a 20% chance of getting what you order. If its correct when you do get it, well,, that's a crap shoot.

 

[Doug Beach]

Unless you order from PTG, then you have about a 20% chance of getting what you order. If its correct when you do get it, well,, that's a crap shoot.

Order it from JGS or Manson. It’ll be perfect. Who cares about the wait?