|
Forum Rules | Firearms Safety | Firearms Photos | Links | Library | Lost Password | Email Changes |
Register | FAQ | Calendar | Search | Today's Posts | Mark Forums Read |
|
Thread Tools | Search this Thread |
August 30, 2014, 09:07 AM | #1 |
Senior Member
Join Date: March 21, 2012
Location: Connecticut
Posts: 2,378
|
You guys think the chamber was cut too tight?
Recently had a rifle rebarreled and I have been unable to resize the brass sufficiently to allow smooth bolt closure. The bolt with close but it is very stiff after resizing. I have 3 different sizing dies and 2 shell holders. Two of the dies are RCBS FL sizing dies and 1 is a redding body die. I have all of them screwed down enough to touch the shell holder. I also have a hornady chamber headspace comparator.
Measurements My readings prior to and after resizing are the same. Prior to resizing it reads 3.571-3.572. The comparator is 2" long so essentially the reading is 1.571-1.572. The SAAMI Spec sheet reads 1.578-.007, I'm assuming that means between 1.571 and 1.578, which would mean my chamber was right at the minimum, probably where is should be. Just below the shoulder my resized cases read .416, the SAAMI Spec sheet lists is at .417. At the base my resized cases read .462 the SAAMI spec sheet lists .468. I believe SAAMI specs are max, probably maximum, not sure where dies are engineered to, probably middle of the road. Seems like my chamber readings are all on the low end but within spec. Cases are trimmed to 1.902 Cases were new to begin with. One last night, new brass also stiff to close. What do you guys think? Last edited by 1stmar; August 30, 2014 at 09:26 AM. |
August 30, 2014, 09:36 AM | #2 | |
Senior Member
Join Date: August 1, 2010
Location: Tampa Bay
Posts: 4,556
|
Quote:
Usually a simple fix. "Touching" the shellholder may not be enough. Raise the ram, screw the die in another 1/2- 3/4 turn or so until the press cams over HARD. You need to take out the slack- usually this will solve the problem.
__________________
Remington 700/Savage Rebarreling /Action Blueprinting 07 FFL /Mosin-Nagant Custom Shop/Bent Bolts Genuine Cerakote Applicator www.biggorillagunworks.com |
|
August 30, 2014, 09:37 AM | #3 |
Senior Member
Join Date: March 22, 2002
Location: In The Hardwoods
Posts: 1,185
|
Is there a shiny place on the brass after you chamber?
|
August 30, 2014, 09:40 AM | #4 | |
Senior Member
Join Date: June 17, 2010
Location: Virginia
Posts: 6,869
|
Question-1: Will a commercial round chamber? If so, measure that round w/ your comparitor and size to that dimension.
Quote:
|
|
August 30, 2014, 09:53 AM | #5 |
Senior Member
Join Date: March 21, 2012
Location: Connecticut
Posts: 2,378
|
Didn't notice any shiney spots, however, I turned the die down another 1/8 and all is good.. Looks like it pushed the shoulder back another .006 so I may have some more adjusting to do. If it was touching the shell holder where is the other .006 coming from, the threads?
|
August 30, 2014, 09:56 AM | #6 |
Senior Member
Join Date: March 18, 2009
Location: Temple, TX
Posts: 956
|
Query: What do you guys think?
Answer: I think you have a minimum chamber. It's not clear in my mind if you were sizing new, never fired brass or if you were re-sizing new brass which had been fired once. If new, never fired factory brass chambers difficultly, then I would guess that your chamber is TOO minimum. If once fired brass is chamberig difficultly after re-sizing, then I would guess that you have a mis-match in tolerances between the chamber and your dies. I had a similar problem with a minimum chambered .300 win mag. I don't know if die makers still do this or do it for free, but I called the die maker, RCBS, and RCBS directed me to return the full length re-sizing die with a fired case. The die and the case were returned and the problem was fixed. No charge. Another solution would be to try and "bubba" it by removing metal from either the top of the shell holder or the bottom of the die body. The problem is that this is hard to do while keeping the surface properly parallel. If I wanted to do this, then I would start with the shell holder because if you ruin it, it is cheaper to buy a new shell holder than a new die. Slowly grind a bit off the shell holder until a re-sized case chambers just chambers easily. Of course that shell holder is now dedicated to that die set. I can tell that you are experienced and not a novice and so I am asuming that you are turning the die body down a little bit past where it touches the shell holder. Most die makers recommend that to allow for the "play" in the press and press linkage. |
August 30, 2014, 10:04 AM | #7 |
Senior Member
Join Date: March 21, 2012
Location: Connecticut
Posts: 2,378
|
Hammie, frankly I didn't go the recommended 1/4 turn past. For years I was always a shoulder bump guy and as a result was always backing the die out no pushing it down further. Been reloading for very long time and frankly never had to do this before. Only have 2 custom barreled rifles, one was done by HART and I didnt have to do this. Tight chamber is probably good for a barrel burner, once I went 1/4 past I was able to push the shoulder back enough. Should have thought of it, but just had to before.
|
August 30, 2014, 10:04 AM | #8 |
Senior Member
Join Date: March 18, 2009
Location: Temple, TX
Posts: 956
|
Where is the .006 coming from? The die body?
@lstmar: Yes. And from the linkage, and even a little bit from the press itself. The press will actually stretch and deform a very tiny bit under pressure. Since you're not deforming the press beyond its elastic limits, it bounces back to the orginal dimensions. |
August 30, 2014, 10:07 AM | #9 |
Senior Member
Join Date: March 18, 2009
Location: Temple, TX
Posts: 956
|
@1stmar: I think you're spot on about the turning down. My experience has been the same as yours.
I simply think that you have a chamber which is exactly at the very minimum and your die is just a little bit longer due to tolerances. |
August 30, 2014, 10:34 AM | #10 |
Senior Member
Join Date: September 28, 2013
Posts: 3,769
|
A small base die should fix the problem without having to bump back the shoulder too much.
-TL |
August 30, 2014, 01:17 PM | #11 |
Senior Member
Join Date: April 10, 2008
Location: Alaska
Posts: 7,014
|
If you are not reloading a great deal or need endless life out of the brass you will be fine.
If you cycle the brass through a lot then it will break above the base at 8-15 reloaded (I never got the caliber you have) The decision is how far to push it as you would prefer not to have the case break. Higher power loads will break sooner. Some calibers really not tolerant and break sooner. If you don't mind getting new brass from time to time you are good. If you want to keep using it a lot then a bit less bump back and trail and error as to what works will help and or the shoulder die mentioned. |
August 30, 2014, 01:34 PM | #12 |
Senior Member
Join Date: March 21, 2012
Location: Connecticut
Posts: 2,378
|
Thanks I won't leave the die where it is. I will adjust it so I am only bumping the shoulder .002-.003. I just adjusted it to see if it was the issue. Now that I know for sure, i will adjust accordingly. Frankly a little embarrassed I didn't do this without the post. Every die instruction and reloading manual says to do this. However I always ended up backing off so I stopped doing it and always reversed the process. Measure a fired case and then screw the die down far enough to bump the shoulder. In this case I just stopped when the shell holder hit the bottom of the die thinking I couldn't get anymore out of it. Hey that's what you guys are for...
Last edited by 1stmar; August 30, 2014 at 01:42 PM. |
August 30, 2014, 02:06 PM | #13 |
Senior Member
Join Date: December 6, 2009
Location: Hudson Valley,NY
Posts: 231
|
New Barrel
Most new Barrels are .002 under so your Smith can final cut your chamber to exact headspace. Check with your Smith just to verify your chamber is a finished cut .
|
August 30, 2014, 08:04 PM | #14 |
Senior Member
Join Date: August 23, 2014
Location: Nevada/Ariz/CA
Posts: 1,753
|
I have had that happen with four die sets (different calibers--one being a
416 rem mag). This is due to a mismatch between chamber and die although both can be within specs. My solution has been to grind some metal off the bottom of the die. Easy to do if you can obtain a grinding wheel that can be attached to an electric drill. Obviously use the flat outside surface of the wheel to do the grinding. |
Thread Tools | Search this Thread |
|
|