When to trim ? ... 26 Mar 14
- Thread starter rmist
- Start date
Re: When to trim ?
I trim all my 6mmBR brass to 1.549.. "MY" rule of thumb: once the brass grows PAST 3K in length>>it gets a trim job. ALSO, I find that my first firing, after an anneal job, generally needs a trim.. Not always.. But they grow more easily when "soft" and quite often past my 3K limit.. So they get trimmed..
I trim all my 6mmBR brass to 1.549.. "MY" rule of thumb: once the brass grows PAST 3K in length>>it gets a trim job. ALSO, I find that my first firing, after an anneal job, generally needs a trim.. Not always.. But they grow more easily when "soft" and quite often past my 3K limit.. So they get trimmed..
Re: When to trim ?
Thank you ShootDots...I will get my trimmer set up tonight and start trimming. I was going to use 1.552, but I'll use the 10 thou rule and cut to 1.550. My chamber is 1.560". I have never annealed (want to). I keep having to ask these questions since it's been a long time since I shot anything competitively. Trying to get everything in order again !!
Thanx again,
Rmist
Thank you ShootDots...I will get my trimmer set up tonight and start trimming. I was going to use 1.552, but I'll use the 10 thou rule and cut to 1.550. My chamber is 1.560". I have never annealed (want to). I keep having to ask these questions since it's been a long time since I shot anything competitively. Trying to get everything in order again !!
Thanx again,
Rmist
Shynloco
You can lead a horse to water, but ........
Re: When to trim ?
rmist,
Sorry I missed your post earlier. But to your question about trimming, I trim whenever it needs it. Over the years, I've set my brass length and trimmer for my 6mmbr to 1.550. For whatever reason, the VhitaVuroi manual recommends 1.552. And I measure every piece of my fired brass whenever I reload it and trim it if it's grown. And the main reason why I trim my brass each time is to try to avoid and prevent the infamous carbon ring (that I've read about and been told) might more likely form with the longer brass, however many thousands that might be. Personally I've never experienced it and perhaps it's because I closely monitor my brass. Anal...perhaps, but it works for me.
Alex
rmist,
Sorry I missed your post earlier. But to your question about trimming, I trim whenever it needs it. Over the years, I've set my brass length and trimmer for my 6mmbr to 1.550. For whatever reason, the VhitaVuroi manual recommends 1.552. And I measure every piece of my fired brass whenever I reload it and trim it if it's grown. And the main reason why I trim my brass each time is to try to avoid and prevent the infamous carbon ring (that I've read about and been told) might more likely form with the longer brass, however many thousands that might be. Personally I've never experienced it and perhaps it's because I closely monitor my brass. Anal...perhaps, but it works for me.
Alex
Re: When to trim ?
Alex, I am a little confused. I was always under the belief that short brass and a long chamber neck was the culprit to having a carbon ring form. When I order a reamer I with spec the chamber dimensions so my case OAL is .010 longer than what I will trim my brass to. Some cases do not stretch as much as others and if your die is a good fit to your chamber dimensions and you are very careful with your shoulder bump and closely monitor your case lenght you can get away with even less than .010 clearance. IMO
Shynloco said:
Alex, I am a little confused. I was always under the belief that short brass and a long chamber neck was the culprit to having a carbon ring form. When I order a reamer I with spec the chamber dimensions so my case OAL is .010 longer than what I will trim my brass to. Some cases do not stretch as much as others and if your die is a good fit to your chamber dimensions and you are very careful with your shoulder bump and closely monitor your case lenght you can get away with even less than .010 clearance. IMO
Re: When to trim ?
I believe this is exactly right. The more free space there is in front of the case mouth when in the chamber, the more area can accumulate carbon. It's a balancing act between keeping that area in front of the case mouth to a minimum and still not risk the chance of the case mouth getting squeezed down on the bullet by having it too long and increasing pressure by increasing the force needed to release the bullet.
TimP said:
I believe this is exactly right. The more free space there is in front of the case mouth when in the chamber, the more area can accumulate carbon. It's a balancing act between keeping that area in front of the case mouth to a minimum and still not risk the chance of the case mouth getting squeezed down on the bullet by having it too long and increasing pressure by increasing the force needed to release the bullet.
Shynloco
You can lead a horse to water, but ........
Re: When to trim ?
[/quote]
I believe this is exactly right. The more free space there is in front of the case mouth when in the chamber, the more area can accumulate carbon. It's a balancing act between keeping that area in front of the case mouth to a minimum and still not risk the chance of the case mouth getting squeezed down on the bullet by having it too long and increasing pressure by increasing the force needed to release the bullet.
[/quote]
I can't give you an exact measurement, but my understanding is supported by the above statement of "keeping that area in front of the case mouth to a minimum" and it being a "balancing act." Apparently I've been able to achieve that (or very lucky in which case I need to go to Vegas more often and I hate the place) as I've never had the carbon ring issue crop up in my rifles. But then it also could be because I clean my rifles after every range shooting (or dry patch every 20 rds) and I usually only shoot 35 - 50 rds max at a time at the range without cleaning.
Alex
[/quote]
I believe this is exactly right. The more free space there is in front of the case mouth when in the chamber, the more area can accumulate carbon. It's a balancing act between keeping that area in front of the case mouth to a minimum and still not risk the chance of the case mouth getting squeezed down on the bullet by having it too long and increasing pressure by increasing the force needed to release the bullet.
[/quote]
I can't give you an exact measurement, but my understanding is supported by the above statement of "keeping that area in front of the case mouth to a minimum" and it being a "balancing act." Apparently I've been able to achieve that (or very lucky in which case I need to go to Vegas more often and I hate the place) as I've never had the carbon ring issue crop up in my rifles. But then it also could be because I clean my rifles after every range shooting (or dry patch every 20 rds) and I usually only shoot 35 - 50 rds max at a time at the range without cleaning.
Alex
Lapua40X
California Hunter Education Instructor
Re: When to trim ?
IMO, we're trying to establish a "standard" case length for the 6BR. Ain't no such animal. If you want to know how much to trim your cases, buy a chamber length gauge (http://www.sinclairintl.com/reloading-equipment/measuring-tools/case-gauges-headspace-tools/sinclair-chamber-length-gage-prod32925.aspx) [no, I am not a stockholder in Sinclair International] and determine what the exact length of your chamber is. Decide how much clearance you want between the end of your case and the end of the chamber and trim to that length. Nobody can tell you what the proper case length is for your rifle without that data.
IMO, we're trying to establish a "standard" case length for the 6BR. Ain't no such animal. If you want to know how much to trim your cases, buy a chamber length gauge (http://www.sinclairintl.com/reloading-equipment/measuring-tools/case-gauges-headspace-tools/sinclair-chamber-length-gage-prod32925.aspx) [no, I am not a stockholder in Sinclair International] and determine what the exact length of your chamber is. Decide how much clearance you want between the end of your case and the end of the chamber and trim to that length. Nobody can tell you what the proper case length is for your rifle without that data.
NorCalMikie
Gold $$ Contributor
Re: When to trim ?
First off, you need to know the "actual" meassured length of your chamber. Sinclaie had plugs that fit in a modified case and tell you the length of your chamber. That measurement doesn't change. From that measurement, you decide how long to leave your brass.
If you use "bushing bump dies", you may never need to trim.
I've got BR brass with 20 to 25 firings and resizes and havn't needed to trim.
Standard full length dies will pull the neck of the case longer with each resize. Neck size and shoulder bump dies work the best for long brass life.
First off, you need to know the "actual" meassured length of your chamber. Sinclaie had plugs that fit in a modified case and tell you the length of your chamber. That measurement doesn't change. From that measurement, you decide how long to leave your brass.
If you use "bushing bump dies", you may never need to trim.
I've got BR brass with 20 to 25 firings and resizes and havn't needed to trim.
Standard full length dies will pull the neck of the case longer with each resize. Neck size and shoulder bump dies work the best for long brass life.
Re: When to trim ?
+1 on these posts for me. I also like to use this stuff whenever I get a new rifle as it also lets me check other important measurements.
http://www.midwayusa.com/product/462291/cerrosafe-chamber-casting-alloy-1-2-lb?cm_vc=U112
I purchased a rifle a couple of years ago in 22BR and found out it had a .246 neck which is pretty tight. I was glad I found that out before I tried to reload anything for it.
Nomad47 said:
Lapua40X said:
+1 on these posts for me. I also like to use this stuff whenever I get a new rifle as it also lets me check other important measurements.
http://www.midwayusa.com/product/462291/cerrosafe-chamber-casting-alloy-1-2-lb?cm_vc=U112
I purchased a rifle a couple of years ago in 22BR and found out it had a .246 neck which is pretty tight. I was glad I found that out before I tried to reload anything for it.
Re: When to trim ?
First, [After You've Pushed Back The Shoulders On Your Brass approximately .001" to .002", hopefully with a F/L sizing die] trim 10/1000ths from the end of the chamber for Safety [the safety zone]. Then trim another 10/1000ths to allow for normal neck growth [the neck growth zone].
The way to keep carbon from building up at the end of the chamber is by rotating [about 30 times] a slightly over sized brush with a cleaning compound such as J-B non-embedding bore cleaning compound [where the chamber ends] each time you clean the barrel. Then clean the compound out before inserting the bore guide, prior to cleaning the barrel itself. Verify for buildup with a Borescope if you have one, or borrow one.
When to trim? Anytime before the second 10/1000ths [the neck growth zone] reaches the beginning of the Safety Zone. Some trim at the 15/1000ths dimension back to the 20/1000ths. All of this depends on knowing the length of the barrel's chamber dimensions.
First, [After You've Pushed Back The Shoulders On Your Brass approximately .001" to .002", hopefully with a F/L sizing die] trim 10/1000ths from the end of the chamber for Safety [the safety zone]. Then trim another 10/1000ths to allow for normal neck growth [the neck growth zone].
The way to keep carbon from building up at the end of the chamber is by rotating [about 30 times] a slightly over sized brush with a cleaning compound such as J-B non-embedding bore cleaning compound [where the chamber ends] each time you clean the barrel. Then clean the compound out before inserting the bore guide, prior to cleaning the barrel itself. Verify for buildup with a Borescope if you have one, or borrow one.
When to trim? Anytime before the second 10/1000ths [the neck growth zone] reaches the beginning of the Safety Zone. Some trim at the 15/1000ths dimension back to the 20/1000ths. All of this depends on knowing the length of the barrel's chamber dimensions.
Joe Maisto
jam711
Re: When to trim ?
Rmist;
If you keep them just .010 under your chamber, you are asking for trouble.
You never want that case to be that close to the chamber length.
rmist said:
Rmist;
If you keep them just .010 under your chamber, you are asking for trouble.
You never want that case to be that close to the chamber length.
Re: When to trim ?
jam711: What you are saying is dependant on the person doing the loading. I measure my brass after each and every sizing. 6ppc's and 6BR's that have very minimal case stretching are kept within .005" of the actual measured chamber length for each chamber. Example: 6BR chambers that have a measured 1.570" length are never left longer than 1.565". These cases can go 6 or 7 loadings without any trimming required, and when they do need it, it's about .003" that is removed.
Cases like the 222, 223 and 308 that do stretch more are measured after every sizing and kept to within .010" of the chamber length's. Example: a Krieger 308, cut with my reamer has a chamber length of 2.020" and that brass is never left longer than 2.010". These cases need trimmed about every other loading and I usually remove about .005".
For others who by their own admission seldom, if ever know their chamber length's, and seldom if ever measure and trim their brass, are the ones protected from their own lack of concern, by the recommendation that their brass be over-trimmed, a lot shorter than it needs to be.
My "system" has worked for me for many years now, without any problems, and without ever having a carbon ring buildup. All as verified with my borescope.
jam711: What you are saying is dependant on the person doing the loading. I measure my brass after each and every sizing. 6ppc's and 6BR's that have very minimal case stretching are kept within .005" of the actual measured chamber length for each chamber. Example: 6BR chambers that have a measured 1.570" length are never left longer than 1.565". These cases can go 6 or 7 loadings without any trimming required, and when they do need it, it's about .003" that is removed.
Cases like the 222, 223 and 308 that do stretch more are measured after every sizing and kept to within .010" of the chamber length's. Example: a Krieger 308, cut with my reamer has a chamber length of 2.020" and that brass is never left longer than 2.010". These cases need trimmed about every other loading and I usually remove about .005".
For others who by their own admission seldom, if ever know their chamber length's, and seldom if ever measure and trim their brass, are the ones protected from their own lack of concern, by the recommendation that their brass be over-trimmed, a lot shorter than it needs to be.
My "system" has worked for me for many years now, without any problems, and without ever having a carbon ring buildup. All as verified with my borescope.
Re: When to trim ?
Hello All,
I have a question concerning reamer dimensions since this is going in another direction. For a lack of dimensions on factory barrels chambers, I have always used the .010†trim length that all the reloading manuals show and have never had any issues. For a custom chamber with a 6 dasher chamber, what do you have the reamer made to for case length? I’m on the assumption that if your brass is 1.550†then your chamber is cut to 1.560†for the case. I work with tight tolerances all the time and .010†isn’t that tight of a clearance. What issues do you have with this dimension?
Thanx again
Hello All,
I have a question concerning reamer dimensions since this is going in another direction. For a lack of dimensions on factory barrels chambers, I have always used the .010†trim length that all the reloading manuals show and have never had any issues. For a custom chamber with a 6 dasher chamber, what do you have the reamer made to for case length? I’m on the assumption that if your brass is 1.550†then your chamber is cut to 1.560†for the case. I work with tight tolerances all the time and .010†isn’t that tight of a clearance. What issues do you have with this dimension?
Thanx again
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