7mm rsaum questions
Moderator: Mod
-
- Posts: 1453
- Joined: Mon Aug 22, 2011 6:33 pm
Geoff,
I am not saying yours and Adams conclusions on your observations are not correct (and could be) but I would add a little side of caution. Other things can be happening as well (as per Bruces suggestion and many others including the reamer spec's aren't correct).
Some of the top level shooters I know still run <2 thou clearance on 1000 yard work with great success. 3 thou is generally considered adequate and slipping a projectile in a fired case is not an ideal test due to various rates of springback etc. I don't think Adam intended that his "rule of thumb" was meant as a scientific test method. You can certainly have a situation where you cannot slip a projectile back in the fired case but there is no impingement under firing.
BUT - if the outcome worked for you guys then that is the important thing and as I said before - I have no problem with lots of neck clearance.
I am not saying yours and Adams conclusions on your observations are not correct (and could be) but I would add a little side of caution. Other things can be happening as well (as per Bruces suggestion and many others including the reamer spec's aren't correct).
Some of the top level shooters I know still run <2 thou clearance on 1000 yard work with great success. 3 thou is generally considered adequate and slipping a projectile in a fired case is not an ideal test due to various rates of springback etc. I don't think Adam intended that his "rule of thumb" was meant as a scientific test method. You can certainly have a situation where you cannot slip a projectile back in the fired case but there is no impingement under firing.
BUT - if the outcome worked for you guys then that is the important thing and as I said before - I have no problem with lots of neck clearance.
-
- Posts: 2900
- Joined: Sun Jun 19, 2005 4:07 pm
but
0.004 MUST be right, because that is what they say on 6mmbr
keep safe,
bruce.
0.004 MUST be right, because that is what they say on 6mmbr
keep safe,
bruce.
"SUCH IS LIFE" Edward Kelly 11 nov 1880
http://youtu.be/YRaRCCZjdTM
http://youtu.be/YRaRCCZjdTM
-
- Posts: 2181
- Joined: Fri Jun 26, 2009 8:21 pm
-
- Posts: 1052
- Joined: Fri Jun 13, 2008 12:22 am
Dave,
No problems, I hear what you're saying. I've neck turned just a few cases for experimentation. What I will do for next weekend is I'll test both, turned necks & non turned cases all once fired. I 'll post the results as in smallest group size, 10 shot groups. 180VLD with 2217 & 15 thou jammed.
300yds should be ok.
Geoff
No problems, I hear what you're saying. I've neck turned just a few cases for experimentation. What I will do for next weekend is I'll test both, turned necks & non turned cases all once fired. I 'll post the results as in smallest group size, 10 shot groups. 180VLD with 2217 & 15 thou jammed.
300yds should be ok.
Geoff
-
- Posts: 2900
- Joined: Sun Jun 19, 2005 4:07 pm
-
- Posts: 1290
- Joined: Mon Dec 29, 2008 10:29 pm
DaveMc wrote:Geoff,
I am not saying yours and Adams conclusions on your observations are not correct (and could be) but I would add a little side of caution. Other things can be happening as well (as per Bruces suggestion and many others including the reamer spec's aren't correct).
Some of the top level shooters I know still run <2 thou clearance on 1000 yard work with great success. 3 thou is generally considered adequate and slipping a projectile in a fired case is not an ideal test due to various rates of springback etc. I don't think Adam intended that his "rule of thumb" was meant as a scientific test method. You can certainly have a situation where you cannot slip a projectile back in the fired case but there is no impingement under firing.
BUT - if the outcome worked for you guys then that is the important thing and as I said before - I have no problem with lots of neck clearance.
Yep exactly Dave! It's not a hard and fast rule but I didn't find any noticeable loss in accuracy running MORE clearance where some people have found a dramatic loss in accuracy running less. So out of the desire to have something that was consistently accurate with less chance of any issues relating to cleanliness I decided on 4 thou
-
- Posts: 837
- Joined: Fri Jul 23, 2010 10:21 pm
- Location: Gippsland, Victoria
johnk wrote:bruce moulds wrote:but 0.004 MUST be right, because that is what they say on 6mmbr bruce.
That's where I went wrong. I listened to John Giles who told me .0025-.003" clearance for the neck he cut me.
John also cut my 7mm neck and it shoots ok with 0.003" clearance but another rifle that I had built by another smith, with the same stated neck diameter of .312" needed 0.004" clearance.
I put this down to reamer wear. Its very easy for a reamer to loose its sharp edge in this area and the resulting neck diameter may not agree with the .312' stamped on the barrel........
-
- Posts: 443
- Joined: Tue May 17, 2016 5:50 pm
Re: 7mm rsaum questions
Apologies for dragging an old topic back but didn't want to create another...
Question: what are people using to next down from 300 SAUM to 7mm. I used my Redding bushing die that does not go all the way to the shoulder junction. As a result I have turned too much at the unsized portion and now have twice fired cases with neck separation... splitting and falling off.
I'm clearly not doing something right and although I now have 100 new cases to throw in the bin, I would prefer not to have 200....
Thanks for any advise.
Albert
Question: what are people using to next down from 300 SAUM to 7mm. I used my Redding bushing die that does not go all the way to the shoulder junction. As a result I have turned too much at the unsized portion and now have twice fired cases with neck separation... splitting and falling off.
I'm clearly not doing something right and although I now have 100 new cases to throw in the bin, I would prefer not to have 200....
Thanks for any advise.
Albert
Albert
Rosedale Rifle Club
Australian Points Series
Rosedale Rifle Club
Australian Points Series
-
- Posts: 177
- Joined: Tue Mar 08, 2011 11:04 am
- Location: NSW
Re: 7mm rsaum questions
Best way is a form die cut with the reamer for the chamber.
Basically a threaded piece of old barrel with the reamer run into it and it works like a full length sizer ask your Gunsmith if they can make you one up?
Basically a threaded piece of old barrel with the reamer run into it and it works like a full length sizer ask your Gunsmith if they can make you one up?
Cheers
Michael Singleton
Michael Singleton
-
- Posts: 969
- Joined: Wed Jul 22, 2009 12:37 am
-
- Posts: 1978
- Joined: Sun Jun 19, 2005 9:37 pm
- Location: Adelaide South Australia (CTV)
Re: 7mm rsaum questions
ajvanwyk try making a neck bump (no bush) from a blank Newlon [url]http://www.newlonprecision.com/
[/url]
or Wilson
With your reamer
RB
[/url]
or Wilson
With your reamer
RB
Return to “Equipment & Technical”
Who is online
Users browsing this forum: No registered users and 90 guests