Sorting 22 with a rim guage

I had asked a question in another thread, and thought it would be best to start a new thread on the topic. A recent indoor 900 using 22 had me scratching my head over where some of my bullets were going. About two months ago I had started using paper box CCI SV instead of RWS Rifle Target or Eley Target in my Hammerli X-esse for practice and indoor 25 yard competition, and some of the shots seemed odd. Since I only started shooting in 2012 and competing in 2013, CCI was hard to find for a while.

In the interest of figuring out what was going on, I sorted out about two bricks of CCI SV by checking rim thickness. I also measured the rim reliefs in the bolt of my Ruger Mark III (0.045") and the slide of the Hammerli X-esse (0.040").

Here's the breakdown on CCI SV rim thickness:

9 between 0.045" - 0.046"
145 between 0.043" - 0.044"
584 between 0.042" - 0.043"
314 between 0.041" - 0.042"
3 between 0.040" - 0.041"

50 round boxes of Eley Club, Eley Target and RWS Rifle Target measured at 0.039" to 0.040" with much better rim thickness consistency, with most being at 0.039".

While this rainy Saturday afternoon check was tedious, since I plunk check my 45 ammo before competition I like making sure my 22 will at least feed reliably too. It gave me a chance to knock the bigger wax chunks off too. It's not likely I'll be able to do any range testing before the next 900 and realize the best test would be to shoot for groups in a rest or off a sandbag.

Researching the topic at various websites (usually rifle shooters) covers the whole spectrum of data and opinion that sorting by rim thickness matters and doesn't matter. When the rim measurements are at or below SAAMI specs I wonder about their measuring, or if their measuring fixture had a deep bevel. I think it was a good process to find odd rounds that would be better for practice use, but so far can't say if sorting like this improved accuracy in a pistol. Weighing and checking for concentricity doesn't seem worth the time for pistol use.

Stephen

Checking rim thickness weeds out the odd rounds.  This makes the rest of the sample more consistant.  It is a lot better to just buy a higher quality ammo to start with.

Dave C.

To really determine if spending time sorting provides a benefit for you and your guns you will need to collect some data from your pistol/ammo combinations.  It should involve shooting several 10 shot groups with sorted and unsorted ammo from a ransom rest at 50 yds.  

Then ask these questions about your data you now have

What difference do you see in group sizes?
How do these group sizes compare to the size of the x-ring?
Now will sorting make a difference for you shooting at 50 yds?

My pistol will shoot an unsorted CCI group at a 1/2" from a ransom rest.  I am sure sorting would not gain me any advantage.

BUT......What is your headspace..????? 99% of all bullseye shooters do not know the headspace...in any of the three guns..  Most rifle shooters know their headspace...
Rim thickness and headspace do matter.. A pistol is governed by the same mechanics as a rifle..In fact it is more important in a blow back action pistol, than a bolt rifle.. It's true, that match ammo such as Eley Red is very (the most) consistent of any, not only in rim thickness, but all other aspects.

Is the headspace the relief cut into the bolt or slide? Or is there more to measuring headspace? I measured my Ruger Mark III at 0.045" and the slide of the Hammerli X-esse at 0.040" with very-near, er, vernier calipers, face of bolt to bottom of the rim pocket.

(A revisit of the headspace of the bolt faces of 22s with a better caliper shows the Ruger Mk III at 0.046", the Hammerli X-esse at 0.043" and my S&W M41 at 0.048". It took a while to get consistent measurements.)

The thick CCI rims could also explain why I have seen a slight gap between slide and barrel with CCI chambered in the Hammerli. I had had problems with a lot of SK Standard Plus that was a little light, so I have gotten in the habit of looking at the slide/barrel gap during Slow Fire to make sure there wasn't a fail-to-feed jam.

Yes, the counterbore on the breechface. Both are smaller than the norm.. Ruger has a history of being quite generous, but .045 is less than usual.. Production guns are usually going to be on the + side to accommodate "any" ammo.. Are you getting an accurate reading with calipers.??  .040 is fine if you are restricting  your self to Eley . Years ago I had a V Block modified by E D M to allow adjusting the headspace on Ruger Mark series bolt faces..Every single one was too deep..Excessive headspace also contributes to mis fires..

I tested the calipers with thickness gauges and the depth against a depth micrometer (test the test equipment), then when taking depth measurements took several to check consistency of readings. Using my depth micrometer for the readings would have been better, but then I would have had to remove the extractors.

(The calipers used have binned and replaced with a better unit.)

That is just how the BR 50 shooters do it.  .22LR Bench Rest rifles at 50 yards.

I have found that even the most expensive Pistol Match ammo varies all over the place. 

The most consistant ammo was the older Remington Pistol Match and Peters Pistol match.

Jerry

Sounds a little like a catch 22 kind of thing. Practice with less expensive ammo that has a thicker rim and get zero misfires. Switch to the good stuff for the big match and find out you have a little more headspace then you thought you did and get a bunch of misfires. Of course they won't actually misfire when you are checking your zero or even during slow-fire. Yes. That was the voice of experience. I had to replace the bolt on my 41 when it didn't like 10x anymore. The cheap Federal or Remington would have probably made it through the match.

Len

I never trusted the General brand calipers used in the beginning of this thread, the three functions on it rarely agreed with each other. They have been binned and I am now enjoying using a nice piece of Mitutoyo gear, a 500-196-30, which gives me the same readings as my old Mitutoyo one inch micrometer and an old Starrett depth micrometer.

A revisit of the headspace of the bolt faces of 22s with a better caliper shows the Ruger Mk III at 0.046", the Hammerli X-esse at 0.043" and my S&W M41 at 0.048". It took a while to get consistent measurements.

I believe the sorting has made the shots more consistent, but unless I Ransom Rest to test performance it may just be a mental benefit.

The most accurate way is to use known standards...

Jerry,
Thanks for your polite suggestion earlier in the thread to recheck my work. Many years ago in mechanic school my instructors would have torn up my tear-down sheet and given me a new one along with a dope-slap and instructions to go do it again.

Stephen

Sa-tevp..
I'll post some pics later...But, years ago in my quest for 1/2 inch 22 groups, I bought, begged and borrowed samples of every brand of 22 ammo I could find.. I dissected each brand and measured everything.. Bullet sizes, bullet bases, every possible case dimension, examined powder charges, etc.. Everything I could find and think of. One glaring error in every brand except Eley, is random primer compound smears on the inside of the case walls. Eley has the closest most consistent tolerance of any ammo, bar none.. The quality control is amazing.. Having worked in the mass production industry, I was amazed.. That's what we are paying for, and why it is so consistently accurate. The custom ground reamers I use were based completely on Eley dimensions.. I have tested countless .22 pistols, with a variety of ammo.. I don't even bother with anything but Eley.. Every single gun shot Eley better than any other brand..

Sorry for taking so long.. These fixtures give very accurate repeatable results within tenths...  The 41 breechface on this one is .050.. Not unsual and of course the Eley is .0415 which is very uniform among ERB..
For Ruger bolt faces, I had the large V Block EDMed to clear the cocking lugs. This allows the bolt face to be ground to the desired headspace.