.22 lr rim thickness
- Thread starter William Colbert
- Start date
This is a question directed at the guys that measure rim thickness. I weight sort for my F-Class 22RF matches and am a believer. That said at the end of scooting the score targets I have gone back to the sighter target and fired a group using the high end and low end weighed ammo and usually cannot find much vertical different.
If you weight sort and then rim sort or visa versa, how many matched rounds do you get out of a carton of 10 boxes.
If you weight sort and then rim sort or visa versa, how many matched rounds do you get out of a carton of 10 boxes.
Pete Wass
Well-known member
What I believe matters
is what BC identified years ago, what he called the "working length" of the ammo. More specifically, the actual overall length of the loaded round, measured from where the driving bands engage the lead or lands and the base of the rim, where it touches the face of the barrel. I have a gauge I use to make this measurement and I have measured cases of ammo over the years. Good shooting ammo tends to be the same length, from my exploration.
This makes scene when one compares that to CF ammo. Exact AOL's of CF ammo can make all the difference between zero groups and .250" groups and the way I tune CF ammo. So, the reason becomes, to try to get bullet strikes to occur in the same place, ammo with the same AOL are very likely to do that.
One must still buy test lots to find the length one needs and then if one is interested in trying to wring out the most accuracy they can, measure all of it and sort it. It really doesn't take all that long to measure a case of ammo. It's what I do and have for a few years. Makes me feel better, at least, if nothing else. I segregate by .001" and typically find the vast majority of the rounds will be no longer than .002" in length difference. what sorting does, potentially is to wed out rounds that are a lot too long or too short. I have found Eley to be the least consistent, AOL wise in comparison to Lapua. There have been periods when Eley has been very consistent but not in the past few years. Its easy to tell which lots are best. Just look at the number of boxes left in inventory a few days after new ammo lots are announced. It is possible to find good stuff but hard to get ahead of the maddening crowd.
Pete
is what BC identified years ago, what he called the "working length" of the ammo. More specifically, the actual overall length of the loaded round, measured from where the driving bands engage the lead or lands and the base of the rim, where it touches the face of the barrel. I have a gauge I use to make this measurement and I have measured cases of ammo over the years. Good shooting ammo tends to be the same length, from my exploration.
This makes scene when one compares that to CF ammo. Exact AOL's of CF ammo can make all the difference between zero groups and .250" groups and the way I tune CF ammo. So, the reason becomes, to try to get bullet strikes to occur in the same place, ammo with the same AOL are very likely to do that.
One must still buy test lots to find the length one needs and then if one is interested in trying to wring out the most accuracy they can, measure all of it and sort it. It really doesn't take all that long to measure a case of ammo. It's what I do and have for a few years. Makes me feel better, at least, if nothing else. I segregate by .001" and typically find the vast majority of the rounds will be no longer than .002" in length difference. what sorting does, potentially is to wed out rounds that are a lot too long or too short. I have found Eley to be the least consistent, AOL wise in comparison to Lapua. There have been periods when Eley has been very consistent but not in the past few years. Its easy to tell which lots are best. Just look at the number of boxes left in inventory a few days after new ammo lots are announced. It is possible to find good stuff but hard to get ahead of the maddening crowd.
Pete
C.L. Peterson
Active member
Pete,
Another thing I have really found that works, but you can only do one box at a time.
Take one box, hold it over your head and(here’s the hard part) stand on one foot and spin around three times and scream, really loud “I am king of the world”.
Usually this works, but if not, repeat the excercise wearing your girlfriends lipstick.
Rimfile Bullets
1. measuring rimfire ammo is a waste of time
2. never say where self-loaded or home-made was illegal (only by someone who was afraid to get beat).
3. I was the "first" person to make jacketed bullets for 22 rimfire and pointed lead bullets.
4. I made dies to help reload--powder was main problem. Bullets shot well with right weight.
due to business, I have set aside my experimental work for the time being.
Bill (The Man, The Myth, The Legend)
1. measuring rimfire ammo is a waste of time
2. never say where self-loaded or home-made was illegal (only by someone who was afraid to get beat).
3. I was the "first" person to make jacketed bullets for 22 rimfire and pointed lead bullets.
4. I made dies to help reload--powder was main problem. Bullets shot well with right weight.
due to business, I have set aside my experimental work for the time being.
Bill (The Man, The Myth, The Legend)
It's like a moth to a flame or a sucker to a night crawler, you just can't not do it.
Pete
http://benchrest.com/attachment.php?attachmentid=21757&stc=1&d=1542480213
I know you’re retired, hopefully you get residuals from this.
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I have no skin in this game but looking at the IR 50/50 website
THE 3 Gun LIST
back to The List
The List is a point based ranking system that determines the top USRA-IR50/50 competitors in the United States. Hall of Fame points will be awarded for:
The List Champion
Top 25- aka “The List Box”
Caps numbered by place will be awarded to the top 25 places.
Place 39 Pete Wass
Matches 48
Points 39.183
Place 93 Tim Simbari
Matches 24
Pointa 29.173
Then when I look at the sporter scoreline page Pete Wass #9 Tim #55
10.5 Score Line Pete #56 Tim #41
13.5 lb Score Line Pete #51 Tim #55
UL Score Line Pete #71 Tim #85
looks as if pete shoots more matches. He must enjoy himself to engage in the pastime that frequently. Looks like he travels some too. Good job Pete, and with barrels you fitted. Have fun this winter.
THE 3 Gun LIST
back to The List
The List is a point based ranking system that determines the top USRA-IR50/50 competitors in the United States. Hall of Fame points will be awarded for:
The List Champion
Top 25- aka “The List Box”
Caps numbered by place will be awarded to the top 25 places.
Place 39 Pete Wass
Matches 48
Points 39.183
Place 93 Tim Simbari
Matches 24
Pointa 29.173
Then when I look at the sporter scoreline page Pete Wass #9 Tim #55
10.5 Score Line Pete #56 Tim #41
13.5 lb Score Line Pete #51 Tim #55
UL Score Line Pete #71 Tim #85
looks as if pete shoots more matches. He must enjoy himself to engage in the pastime that frequently. Looks like he travels some too. Good job Pete, and with barrels you fitted. Have fun this winter.
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Ok, website politics aside.
A few years ago I made a gauge to check from inside the the rim to the top driving band, just like Mr.Wass was referring to.
The results were very interesting and a few of my friends made one too as we agreed that the 'luxury' of precisely seating projectiles as with centrefire reloading was not possible with rimfire ammunition.
Sure we wasted a lot of time measuring rim thickness and weighing the ammo and soon reached the conclusion that the quality control of modern 'top shelf' rimfire ammunition is very good.
So further investigation revealed discrepancies between the distance between the inside of the rim and the driving band (effective length).
Using the gauge to batch decent rimfire ammunition (Eley Tenex) it soon became apparent that a few thousands of an inch in the 'working length' made a measurable difference to the impact point. Maybe because the 'jump' was different, who knows what this does to the pressure?
Not much, but it's the difference between a 9 and a 10.
I have attached a typical photo of the results. L= 0.002" longer than the average length, S= 0.002"
" shorter than the average length (about 20% of a typical box of Eley Tenex)
In the tight match chamber of my ancient Annie '54 apparently length does make a difference. All targets were shot at 50m outdoors on a very calm day.
Just my observation from down under.
* Doggie *
A few years ago I made a gauge to check from inside the the rim to the top driving band, just like Mr.Wass was referring to.
The results were very interesting and a few of my friends made one too as we agreed that the 'luxury' of precisely seating projectiles as with centrefire reloading was not possible with rimfire ammunition.
Sure we wasted a lot of time measuring rim thickness and weighing the ammo and soon reached the conclusion that the quality control of modern 'top shelf' rimfire ammunition is very good.
So further investigation revealed discrepancies between the distance between the inside of the rim and the driving band (effective length).
Using the gauge to batch decent rimfire ammunition (Eley Tenex) it soon became apparent that a few thousands of an inch in the 'working length' made a measurable difference to the impact point. Maybe because the 'jump' was different, who knows what this does to the pressure?
Not much, but it's the difference between a 9 and a 10.
I have attached a typical photo of the results. L= 0.002" longer than the average length, S= 0.002"
" shorter than the average length (about 20% of a typical box of Eley Tenex)In the tight match chamber of my ancient Annie '54 apparently length does make a difference. All targets were shot at 50m outdoors on a very calm day.
Just my observation from down under.
* Doggie *