204 Ruger reamer specs
- Thread starter EdwinD
- Start date
EdwinD-- I'm certainly no "expert" when it comes to neck reamer specs, but I STRONGLY urge you to check out the validity of the recommendation that your chamber neck be cut to .234". I have a Savage 12VLP in .204 Ruger and the OD at the neck of my loaded rounds measures .226". If your loaded rounds are the same as mine and you have your reamer built to cut a .234" neck, you will definitely have a "No Neck Turn" chamber!!!! You will have a VERY SLOPPY "No Neck Turn" chamber!!!!!
In the new 7th Ed. Hornady Reloading Manual and in Sierra's casing drawings, they list the OD of the .204 Ruger casing at 0.231, but that is quite a bit larger than the neck in the chamber of my .204 Ruger. If your loaded round did measure .231", then a .234" neck would be a good dimension for the reamer to give you a good no turn neck. I'd urge you to check a few more places and get a few more opinions before you order your reamer. Talk to Dave Kiff at Pacific Tool and Gauge.
In the new 7th Ed. Hornady Reloading Manual and in Sierra's casing drawings, they list the OD of the .204 Ruger casing at 0.231, but that is quite a bit larger than the neck in the chamber of my .204 Ruger. If your loaded round did measure .231", then a .234" neck would be a good dimension for the reamer to give you a good no turn neck. I'd urge you to check a few more places and get a few more opinions before you order your reamer. Talk to Dave Kiff at Pacific Tool and Gauge.
Sorry this has taken me so long to get back here, but I haven't been surfing the Internet much the last few days.
Anyway, my first measurements that I listed at .226 OD for loaded rounds were just done with my digital caliper,not always the most accurate tool to use for fine measurements). To get a more accurate measurement, I just went downstairs to my reloading room and used my Mitutoyo tubing mic and came up with the following:
My WW loaded casing with the 40 gr. Nosler BT bullets seated in the neck measured .227". There were a couple that measured .2272", but they were the exception. These were casings that had been fired two times and neck sized after each firing with a .224" Redding Type S bushing neck sizing die with the TiN bushing.
My Hornady casings loaded with the 32 gr. Sierra BlitzKing bullets seated in the neck also measure .227", with one or two going to .2271". These casings have been fired 4 times and neck sized with the same bushing as the WW casings.
The thickness of the necks on both the WW brass and the Hornady brass is not exactly the same all the way around the neck. It varies in thickness from about .0112" on the thin side to .0121" on the thick side. So, if I add these two neck wall thickness and then add the diameter of the bullet I get:
.0112" + .0121" = .0233" + .204" = .2273" which is pretty close to the measurement of .2270" to .2272" that I got off my loaded rounds when using the tubing mic.
For your loaded round OD measurement of .231" your neck wall thickness would have to average .0135" and that is thicker in the neck walls than the brass that I have worked with so far.
The OD of my fired casings measures to .230" to .231", so figuring a fired casing neck shrinks about .001" smaller than the chamber neck ID when it cools a wee bit, my chamber neck is about .231" to .232" ID. Your loaded rounds that measure .231" would be an extrmely tight fit in my chamber. Why my chamber seems to be .231" to .232",just guesstimating from the OD of the fired casings) is a mystery to me, but that's the measurement of my fired casings--both the fired Hornady and the fired WWs measure that way.
I don't think I'll do a chamber mold to get a better measurement though--sorry. I think that for my rifle's chamber I'd have to say my bushing size and my loaded round size is just fine. I guess these measurements of mine and yours just go to show you that these rifles are individuals and what works in mine may be totally wrong for yours!
I would urge anyone ordering a reamer to take a half dozen pieces of the brass you are going to use, FL resize them, get them trimmed to your chosen length, chamfer and deburr the necks lightly, and do any neck turning if you intend to go that route. Then run them through your chosen neck sizer to get the necks back to the chosen diameter,I am assuming you are using a neck turner like the K&M where you use a slightly oversized mandrel to get the neck size large enough to fit over the mandrel in the cutter). Next, seat your bullet in the casing neck so the OAL of the casing is to your specifications. Do that with three or four casings and send those into whoever you are going to have do your reamer. You will get a reamer that works with your selection of brass.
If you change the lot number of your brass, you may have to deal with thinner or thicker neck walls and that opens up another can or worms for you to deal with. As long as the neck wall thickness of your brass will allow you to turn it to equal thickness all the way around, and it isn't waaaay smaller in OD when you are done, you should do just fine.
[Edited to correct a spelling error!]
Anyway, my first measurements that I listed at .226 OD for loaded rounds were just done with my digital caliper,not always the most accurate tool to use for fine measurements). To get a more accurate measurement, I just went downstairs to my reloading room and used my Mitutoyo tubing mic and came up with the following:
My WW loaded casing with the 40 gr. Nosler BT bullets seated in the neck measured .227". There were a couple that measured .2272", but they were the exception. These were casings that had been fired two times and neck sized after each firing with a .224" Redding Type S bushing neck sizing die with the TiN bushing.
My Hornady casings loaded with the 32 gr. Sierra BlitzKing bullets seated in the neck also measure .227", with one or two going to .2271". These casings have been fired 4 times and neck sized with the same bushing as the WW casings.
The thickness of the necks on both the WW brass and the Hornady brass is not exactly the same all the way around the neck. It varies in thickness from about .0112" on the thin side to .0121" on the thick side. So, if I add these two neck wall thickness and then add the diameter of the bullet I get:
.0112" + .0121" = .0233" + .204" = .2273" which is pretty close to the measurement of .2270" to .2272" that I got off my loaded rounds when using the tubing mic.
For your loaded round OD measurement of .231" your neck wall thickness would have to average .0135" and that is thicker in the neck walls than the brass that I have worked with so far.
The OD of my fired casings measures to .230" to .231", so figuring a fired casing neck shrinks about .001" smaller than the chamber neck ID when it cools a wee bit, my chamber neck is about .231" to .232" ID. Your loaded rounds that measure .231" would be an extrmely tight fit in my chamber. Why my chamber seems to be .231" to .232",just guesstimating from the OD of the fired casings) is a mystery to me, but that's the measurement of my fired casings--both the fired Hornady and the fired WWs measure that way.
I don't think I'll do a chamber mold to get a better measurement though--sorry. I think that for my rifle's chamber I'd have to say my bushing size and my loaded round size is just fine. I guess these measurements of mine and yours just go to show you that these rifles are individuals and what works in mine may be totally wrong for yours!
I would urge anyone ordering a reamer to take a half dozen pieces of the brass you are going to use, FL resize them, get them trimmed to your chosen length, chamfer and deburr the necks lightly, and do any neck turning if you intend to go that route. Then run them through your chosen neck sizer to get the necks back to the chosen diameter,I am assuming you are using a neck turner like the K&M where you use a slightly oversized mandrel to get the neck size large enough to fit over the mandrel in the cutter). Next, seat your bullet in the casing neck so the OAL of the casing is to your specifications. Do that with three or four casings and send those into whoever you are going to have do your reamer. You will get a reamer that works with your selection of brass.
If you change the lot number of your brass, you may have to deal with thinner or thicker neck walls and that opens up another can or worms for you to deal with. As long as the neck wall thickness of your brass will allow you to turn it to equal thickness all the way around, and it isn't waaaay smaller in OD when you are done, you should do just fine.
[Edited to correct a spelling error!]
EdwinD
I bought a reamer for my custom .204 Ruger from Pacific Tool & Gauge. They have a no neck turn reamer they call their .204 Ruger Match reamer. I had mine altered for a tight neck,.228) but you could order yours without the alteration. The only other modification I did was take the freebore from .057 to .000 at the advice of my gunsmith. That way I would still be able to reach the lands when throat errosion advances.
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I bought a reamer for my custom .204 Ruger from Pacific Tool & Gauge. They have a no neck turn reamer they call their .204 Ruger Match reamer. I had mine altered for a tight neck,.228) but you could order yours without the alteration. The only other modification I did was take the freebore from .057 to .000 at the advice of my gunsmith. That way I would still be able to reach the lands when throat errosion advances.
EdwinD--You are welcome. I'm glad we were able to help in some small way.
skipper-- Thanks for posting the reamer drawing. I have a question I'd like to ask if you would be kind enough to answer. When I look at the drawing, the angle of the shoulder looks to be quite a bit less than 30º and I believe the angle of the shoulder on the .204 Ruger is 30º. I know the drawing lists the angle as 30º, but it doesn't look like it is. Are my eyes playing tricks on me or is that shoulder angle a bit out of proportion on this drawing??? Thanks.
skipper-- Thanks for posting the reamer drawing. I have a question I'd like to ask if you would be kind enough to answer. When I look at the drawing, the angle of the shoulder looks to be quite a bit less than 30º and I believe the angle of the shoulder on the .204 Ruger is 30º. I know the drawing lists the angle as 30º, but it doesn't look like it is. Are my eyes playing tricks on me or is that shoulder angle a bit out of proportion on this drawing??? Thanks.
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