.22LR rim thickness and reliability

I'm using Aguila SuperExtra in my Nelson conversion (which is running and shooting beautifully on the Springfield Loaded frame). The pistol is running reliably with the stock spring. The problem is that out of my batch of ammo, I seem to get one misfire out of every box. I think that the problem is the occasional thin rim on the Aguila. Ammunition from the same lot ran perfectly for a thousand rounds out of my Ruger, which pretty much mangled case rims with an aftermarket firing pin.

49 cases of each box show a shallow, but very distinct strike. I wouldn't personally call it light, it's just not very deep. Misfired rounds show a very shallow strike, or none at all. When I refire these cartridges, they usually work, but still show a lighter-than-normal primer strike. My theory is that since the Nelson unit is designed to be dry-fire safe, what's happening is that the cartridges with the thinnest rims are the ones that are misfiring.

So I'm considering picking up a .22LR rim gauge and sorting out the thinnest standard deviation of Aguila SuperExtra. Once I work through the case I have left, I can switch over to CCI Standard. The misfire problem is at worst slightly annoying now, as a point or two lost in an alibi doesn't mean much in the league shoots I'm doing now. But I'd kinda prefer not to leave anything on the table for winter team shooting.

Good/bad idea?

Before going through the aggravation of measuring rim thickness, I would check headspace.  If that dimension is good, then switch to a product with more consistent rim thickness.  Sorting ammunition by rim thickness for a pistol is, IMHO, not time well spent.

I agree with Richard. If CCI proves more reliable, use it for league and matches. Use up the Aguila in practice. Alibis are part of the game but avoiding them by using the right ammo and maintaining equipment is the responsibility the shooter.

I had the same problem, cleaned the firing pin channel and used the lubricant the pistol shipped with and that seemed to solve the issue.  I'm not saying my problem is yours, but it is one thing to look at if you haven't already and doesn't cost anything other than time.

What mainspring ate you using?
Do they fire if you hit them a second time?
I'm using the ISMI 19# mainspring to keep those problems away.

I also use Aguila super extra standard velocity

Not a 'serious or perhaps useful reply!

I recall hearing about an 'old time' (I resemble that remark these days) smallbore rifle shooter who contended that there was a '9' in every box of ammo. His answer was to shoot each box of ammo in practice until he shot that '9' then put the rest of the box aside for match use.
I guess it would test the concept that there is one misfire in each box.

Bruce

Richard Ashmore wrote:Before going through the aggravation of measuring rim thickness, I would check headspace.  If that dimension is good, then switch to a product with more consistent rim thickness.  Sorting ammunition by rim thickness for a pistol is, IMHO, not time well spent.

I agree. Measuring rim thickness is tedious work.

Fire Escape wrote:Not a 'serious or perhaps useful reply!

I recall hearing about an 'old time' (I resemble that remark these days) smallbore rifle shooter who contended that there was a '9' in every box of ammo. His answer was to shoot each box of ammo in practice until he shot that '9' then put the rest of the box aside for match use.
I guess it would test the concept that there is one misfire in each box.

Bruce

The first thing I do, is pull the bullet and determine if it is the fault of the gun or ammo.. There is so much variation between ammo manufacturers.. Eley is the most consistent with primer compound application.
On conversions, one of the biggest causes of failure to fire, is the extractor.. The extractor and extractor groove in the breechface, must be adjusted and timed to have minimum resistance.. or, as gunk builds up, the slide will not go into full battery. This condition is aggravated by the tendency/urge to install weaker recoil springs to "facilitate function"..
There is much that can be done to the conversions to assist ignition.. My favorite conversion, the Kart, had few such issues..

My nelson does produce a noticeable, consistent but shallow rim strike.  I have a 21# MS.   100 or so CCI SV and 500 Norma Tac22 rounds have all fired without a single misfire though.

mspingeld wrote:I agree with Richard. If CCI proves more reliable, use it for league and matches. Use up the Aguila in practice. Alibis are part of the game but avoiding them by using the right ammo and maintaining equipment is the responsibility the shooter.

The hard part would be actually getting the CCI, due to a state law banning internet sales. It can't be had locally (unless I was willing to support one price-gouging LGS--I don't think even supply/demand justifies $90 a brick for CCI), so I'd have to dig up a private FFL, order online from somebody that's still willing to ship to my state, get the FFL to send his license information to the seller, and then pay him a surcharge when the ammo arrives. Like I said, next time I can get a hold of a case, that's the plan.

Jerry Keefer wrote:On conversions, one of the biggest causes of failure to fire, is the extractor.. The extractor and extractor groove in the breechface, must be adjusted and timed to have minimum resistance.. or, as gunk builds up, the slide will not go into full battery. This condition is aggravated by the tendency/urge to install weaker recoil springs to "facilitate function"..

It goes into battery consistently and smoothly, even on misfires. I verified that early on with a box's worth of slow fire, checking the slide and hammer position after every shot. I had swapped to the lighter recoil spring briefly, but I went back to the stock 9#, which seems to work fine. Extractor and extractor groove are both clean. 

Outthere wrote:I agree. Measuring rim thickness is tedious work.

Oh, I don't mind tedium. Same reason I like reloading. I think I just like the feeling of crafting something.

JayhawkNavy02 wrote:I had the same problem, cleaned the firing pin channel and used the lubricant the pistol shipped with and that seemed to solve the issue.  I'm not saying my problem is yours, but it is one thing to look at if you haven't already and doesn't cost anything other than time.

I cleaned the firing pin channel and lubed with CLP, but I didn't try the MFR stuff. I got some time tomorrow, I think I'll shoot a practice 900 and give it a shot or ninety.

Then, check firing pin contour and polish...The top of the pin should be relieved to compensate for rim collaspe..I would check the firing pin for retraction distance.. How far back does it extend.? This is the most overlooked area... Is there interference between the retaining pin and the frining pin notch..Often the radius needs dressed. How far forward does the pinprotrude? It should not exceed the depth of the headspace by at least .010 to protect the breechface.. As Richard stated, headspace can have an effect. Many .22s have far to much. .043 is considered optimum.. If you are strictly an Eley shooter you can run less.. But the pin needs adjusted for any headspace change.
Hammer face contact..I believe in hammer face contour.. ESPECIALLY,  on .22 conversions. Is the strike force centered..?  Main spring housing bore, spring, and cap..Should be smooth and highly polished. Is the strut dragging anywhere? It may appear that the slide is in battery after a mis fire,  because the hammer drove the slide forward, but the hammer energy was absorbed by the effort.

I had the same problem with aguillla super extra. The quality control in terms of rimm thickness varies a lot from 0.365 to 0.415 or about 2x the variation of CCI. 

I would not measure the rimms just to eliminate squib-by rounds, life is too short and it takes about 1/2 hour to 45 minutes to measure a brick.

I got my brick from the CMP and the bullets had a lot of lube on them some looked like they had white crowns. So I would also check for too much lube as that can lead to a dirty chamber and create some of the problems you cited.  

But if you have time, and a lot of Aguilla then I would recommend measuring cases as 3 or bricks should yeild 1 to 2 bricks of match quality ammo. 

On my Hornady gauge, I found 0.390-0.395 to yield highly accurate ammo as good as green tag or SK

It's something best done while watching Detroit Lions football games...

For what it's worth I have the best luck with the cheaper ammo. The last match I went to I brought what I thought was great ammo. During Sight in I started with Eley Club (orange box). First round went off then the next two were duds. Put them away as I grumbled and brought out Eley Target (yellow box). First round was a dud. Obviously the first thing that goes through my mind is my pistol has a problem (Benelli MP95). Now I'm biting my lip to keep from saying bad things. I didn't want to use my Nelson as I am very disappointed with the accuracy even though it's like a Glock, it will eat any ammo and never malfunction. I brought out CCI SV and finished sight in and went through the 22 stage with no problems. I can't remember the last time I had any duds and at a match I have three within four rounds. What are the chances?

messenger wrote:For what it's worth I have the best luck with the cheaper ammo. The last match I went to I brought what I thought was great ammo. During Sight in I started with Eley Club (orange box). First round went off then the next two were duds. Put them away as I grumbled and brought out Eley Target (yellow box). First round was a dud. Obviously the first thing that goes through my mind is my pistol has a problem (Benelli MP95). Now I'm biting my lip to keep from saying bad things. I didn't want to use my Nelson as I am very disappointed with the accuracy even though it's like a Glock, it will eat any ammo and never malfunction. I brought out CCI SV and finished sight in and went through the 22 stage with no problems. I can't remember the last time I had any duds and at a match I have three within four rounds. What are the chances?

Now remember, Eley QC is substantially superior to almost anything you can name. The rim dimensions are on the low side, which allows for a tighter headspace in match guns.... If your gun has sloppy headspace, Eley just might give mis fires.. But again... Pull the projectile and look for a primer compound void..Ascertain if the ammo is at fault. I haven't had three Eley mis fires in my entire life.. It's all we use..

rich.tullo wrote:I had the same problem with aguillla super extra. The quality control in terms of rimm thickness varies a lot from 0.365 to 0.415 or about 2x the variation of CCI. 

I would not measure the rimms just to eliminate squib-by rounds, life is too short and it takes about 1/2 hour to 45 minutes to measure a brick.

I got my brick from the CMP and the bullets had a lot of lube on them some looked like they had white crowns. So I would also check for too much lube as that can lead to a dirty chamber and create some of the problems you cited.  

But if you have time, and a lot of Aguilla then I would recommend measuring cases as 3 or bricks should yeild 1 to 2 bricks of match quality ammo. 

On my Hornady gauge, I found 0.390-0.395 to yield highly accurate ammo as good as green tag or SK

Rich
I think your decimal point is in the wrong spot..
I have never seen a .0365 rim.. Wow, that's poor quality for sure..

Nah Jerry, just big rimfires. (snicker)

yes , wrong place sorry, but yes you get on or 2 in every 500.

With the MP90 or MP95, a clean chamber important. I start a match with a clean chamber (brushed with a bent .25 cal rifle brush and then having a kroil wet patch on a pull though, finally test the chamber by removing the bolt and dropping in your choice of rounds to make sure that there is no resistance). I shot the MP90 exclusively for 7k rounds (10 months of matches and practice) mostly with CCI STd. I always had to make sure that the chamber was clean before shooting a 900. If I didn't I would have either feed failures or misfires. 

FYI, for me Eley, SK and RWS worked better than CCI as far as reliability went. Any of them would shoot a clean but the edge went to Eley Club or Norma Tac (RWS) for accuracy as well. I never shot anything more expensive than Eley Club.

Jerry Keefer wrote:

messenger wrote:For what it's worth I have the best luck with the cheaper ammo. The last match I went to I brought what I thought was great ammo. During Sight in I started with Eley Club (orange box). First round went off then the next two were duds. Put them away as I grumbled and brought out Eley Target (yellow box). First round was a dud. Obviously the first thing that goes through my mind is my pistol has a problem (Benelli MP95). Now I'm biting my lip to keep from saying bad things. I didn't want to use my Nelson as I am very disappointed with the accuracy even though it's like a Glock, it will eat any ammo and never malfunction. I brought out CCI SV and finished sight in and went through the 22 stage with no problems. I can't remember the last time I had any duds and at a match I have three within four rounds. What are the chances?

Now remember, Eley QC is substantially superior to almost anything you can name.   The rim dimensions are on the low side, which allows for a tighter headspace in match guns.... If your gun has sloppy headspace, Eley just might give mis fires.. But again... Pull the projectile and look for a primer compound void..Ascertain if the ammo is at fault. I haven't had three Eley mis fires in my entire life.. It's all we use..

My MP95 has barely 2 bricks though it. I has mostly been Eley sport (purple box) shot through it. I have never had any duds with it ever. That's why I was so amazed to have three in a row with far more expensive ammo than what I normally shoot in it.