Hooked up the magneto to 3 barrels...


Dirty Civilian
So ive been getting some frstrating and erratic performance out of my 40x lately. Thought maybe a cleaning was in order so i stripped everything out and ran almost a brick of ammo before i started judging performance. Bought 5 different lots of 5 different bullets, yea some did better than others but none touched the performance it once had with any of them. CenterX, lapua biathlon, eley match, eley tenex, eley biathlon all would print 1/4"@50 and better...now im lucky to get 1/2" with the norm being 1". Sk was a cheap alternative for plinking that would give 1/2" consistently and now is 1" as well.

So yesterday my brother in law came over with his cz455 and my dad broke out his Annie 54 for some shooting. I got curious and broke out the magnetospeed since ive never measured velocities and my brother in law wanted the data anyway. We all used two different lots of SK plus, a round and lot proven to give 1/2" and better at 50yrds for all of us.

annie: 5.4sd 1083avg 12es over 10rds
cz455: 3.4sd 1070avg 8es over 10rds
40x: 34sd 1074avg (forgot to rec es) 10rds

we repeated results twice each lot and these results were pretty consistent.

i know each gun has a favorite ammo. But if the ammo is producing those results in 2 guns shouldnt it match numbers (or closer) out of the 40x regardless of accuracy results? Im thinking it may be time for a new barrel but figured id see what the hide has to say. Id be curious to see what you all make of the chrono data.
I don't know you or how much you have shot through you 40x. I know of BR shooters who shoot 60,000 rds per year who do wear out 22lr bbl.'s but in my experience as a more or less casual recreational and sometimes competitive shooter, I have never worn out a bbl. I have seen some whose chamber was damaged by dry firing, and others whose crown was damaged by bad cleaning rods and cleaning practices, and others whose bore was pitted from being left dirty or exposed to moisture and humidity. Before I would fork over for a new bbl, I would closely examine the chamber, throat, bore and crown looking for evidence of wear and tear. Depending on findings you can decide. It may just need to be re-crowned for example. Did your std deviation measure 34?? or 3.4? 34 is really interesting. If that is right, something is truly amiss.



Dirty Civilian
Ive shot probably 10k through it myself. It was a school gun back in the day so i have no idea how much its been shot. I use a bore guide, only clean when i see accuracy drop or it will be stored longer than a month (not often). Crown looks good, i considered recrowning it (i do the work on a lathe) but the sd made me think its not worth the effort. The sd is actually 34....not 3.4. I do not have access to a borescope and for the cost of a decent one i might as well just buy a barrel blank and upgrade anyway. Chamber from what i can tell with a magnifying glass and light look good. No lead looks like it built up at the lead/throat.

the sd bothers me as well...we used tge same box of ammo between the 3 of us ( 10 pulled from another box but same lot/brick.
Original firing pin spring? Sounds like it could be inconsistent ignition.
Interesting theory. But, I'm not afraid to show my ignorance with the following question. To me, it either lights or it doesn't? How could it light enough to discharge but just have a slower MV? Im a center fire guy, so maybe something unique to a rimfire?



Dirty Civilian
Ill have to double check but i believe the spring was swapped about a year ago.

ive decided to buy a new barrel anyway but im still going to fiddle with this guy in the meantime to see whats up. Im going to really strip everything out of the barrel again, reseason with about 200rds and then chrono the eley lots i have left and see what she gives. Ill also throw the barrel in the lathe and freshen up the chrown for good measure. I doubt the crown has that big an impact on tge erratic velocity but ehat the hell.

Ill see if maybe throwing the old FP spring in changes anything also.


Gunny Sergeant
I've seen three 40Xs around here go down with weak firing pin springs, including mine. None of us thought to check MV, but it's appears to be a common failure point.

Talking with the Eley test tech here a few months ago, he claims 10-15 rounds of seasoning are plenty to get consistent results.


Dirty Civilian
I'll have to give the 10-15 a try, I'll likely just hook the chrono up after cleaning and keep shooting...will be good time to practice positional. I was always followed a stripped barrel needed a good 100-200 to reseason but after that it was only 10-20 to season the barrel to a different bullet (switching from SK to Lapua for example).

In any case I wont be able to test anything until I get back from work in another week or 2. I managed to find a new Wolff extra power spring on ebay for $10 shipped so I picked it up to see. If I'm right this gives me the OEM spring, Current spring and Wolff extra power to test. To narrow this down I'll test as follows:

1) Change spring to Wolff, Test
2) Change spring to OEM, Test
3) Change spring to best performance (if any difference), strip barrel, reseason, Test
4) Re-crown, Test

Should give pretty good data for better or worse. I have a shilen ratchet on the way to spin on but bushing/go-guage/etc have a 12 week lead time so I have some time to try crap.
I would chrono the 40X again before you jump to any conclusions.

I concur. Any time I'm punching paper, there's a chronograph out front.
Both with centerfire and rimfire. You will be unhappy with the variations in rimfire mv,
especially with those labeled "match". "Match" has become a sales gimmick,
not an accurate description of the contents of the package. Without the chrono out front,
there's no way to determine if those strays are due to the shooter or the ammunition quality.

2 years, 3 plus cases of assorted Lapua, Eley, RWS, SK, Wolf, CCI, Hornady, Federal,
has shown that anything rimfire is subject to major variations in muzzle velocity, no matter what it's labeled.
It's rimfire, we have no control over the manufacturing process.

My idea of a statistical sampling for quality control verification is a full brick.
Not 10 or 20 shots. I've been disappointed too many times,
with the supposed high end rimfire ammo I've been shipped.

There is an advantage to using an optical chronograph.
It does not affect the rifle, barrel harmonics or setup while shooting/measuring mv's.

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FP spring is the stock one. Swapped it out for a wolff extra power and cleaned the crap out of the barrel. Results just in group size (hooking chrono up tomorrow)are much better. Still not like it used to be but definitely acceptable. Couple of grpups down in 1/4" outside to outside and most 1/2" -5/8" outside to outside. Will be interesting to see what the chrono results show.

now after cleaning (lead out, #9, clp) i slugged and inspected the bore. About 1/2" in front of the lead i noticed a ring that I could just not scrub out. Also the bore looked like it had the appearance of being bubbly but no rust.

When i slugged it felt pretty consistent up until 2" from the muzzle where it felt like it started to choke. But slug diameter had zero variation from any of the others.
1) chamber pushed a slug straight through. .2215 x .2190
2) chamber pushed just short of choke. .2215x.2190
3) muzzle just past choke. .2215x.2190
4) chamber just past lead. .2215x.2190

Slugs extreamly uniform but no idea why im feeling a choke when none measure.

going to chrono tomorrow and will likely freshen the crown up for good measure.


Shoots both eyes closed
That ring you speak of is most likely what is messing with you. Carbon rings suck to get out and wreck havoc on a lot of stuff. Search for Orkans barrel cleaning with CLR which I have found to make it easier to remove.
Ill have to do that. I went at it again hard yesterday. Filled the barrel with Lead Out and let it sit for 30 min, scrubbed with a new brush for a good 10min and patched it all out. The blistery look is now gone but i can still see the damn carbon ring. Its only visible at 6 Oclock so maybe Orkans way can help.

i reslugged the barrel and found 2 tight spots and not where id want them. One within the first inch measuring about .2214 (likely due to carbon ring) and one about mid way at .2215 with the muzzle being .2216 - .2217. So even if i got the carbon ring out id have to chop my bbl to like 13" to get the choke where it should be.

slapped the chrono on and eley gave me an 8.9sd but SK gave me 23sd. The target results show this also.

its at least better than my brother in laws CZ now haha. Ill likely just leave it as is and wait for my reamer to come in. Lapping is too much work when i have a nice barrel sitting here.

EDIT: Also thanks for the tip on the FP spring. I dont think i would have tried that for a while and it made a significant difference.
Yes. Ideally you want your widest at the breach and tightest at the muzzle. Its ok if its not a uniform tightening as long as it doesnt get tight then loose. Clearly mine is not like that. Ive got just about every "bad" trademark in my barrel...but the grooves are incredibly uniform all the way through (very round) which i think is what is saving it from shooting like complete crap.
what is the reasoning for this? thinking of cutting my 20 down to 16
I don't know the physics but IIRC Anshutz barrels are the same way- and I thought you could almost see that the barrel profile was a bit different? When Jelrod put my Benchmark barrel on, it was a bit longer than I really wanted, and the Benchmark people told him not to chop off a lot of length beyond crowning. I don't know how much is done or how, or if everyone does it. I'd just check around with the manufacturer before hacking length off the muzzle end.
Lead...unlike copper has no spring to it. When the lead is shaped to say 0.2215" it will stay 0.2215" where as copper may "rebound" back to 0.2217". Having the tightest spot at the muzzle guarantees the bullet was gripped and guided out of the bore rather than being loose and "rattling" in the bore. Also with an undersized bullet you can expect some type of gas escape. This can screw with MV fluctuations....maybe induce some type of yaw if enough pressure screws with the bullet as it leaves.

this is my understanding of barrels for rimfires. And not every factory checks for choke at the end of their barrels. Id guess anschutz has some method to do this or they wouldnt have such a good record of producing accurate rifles but i cant say for sure what they do.
I have an old Mossberg M44b. I believe its still original. It does have an old Variable scone the predates the rifle. I was told that these were used for sniper training during WWII. To date this is still very much like a laser beam. Its not picky for it digestive desires either. Just saying this as I have personally shot about about 4-5k rounds through it myself in the last few years. I would guess that it has more rounds than most might be able to imagine. Its still crazy accurate. I didn't know a 22 rimfire could burn out a barrel. Is this something that happens frequently?
Honestly at this point I believe it may have just been the FP spring and good cleaning it needed...After the hard scrubbing I ran about 700 rounds through the barrel prepping for a match and the morning of match day I zeroed and printed two groups I could cover with my pinky nail including cold bore. Its possible it just needed a really good scrub and took a lot of rounds to season to its liking. I can definitely say the new firing pin spring helped bring my SD/ES back into order and maybe it was just due again for that good cleaning to bring everything together. I dont really believe it is easy or even possible to wear out the rifling of a 22lr but the lead I believe could be eroded over time being so close to the combustion.

I've also read up on Orkan's carbon ring cure and if it starts acting up again may give it a go. I'm too nervous to clean it now that it is shooting well...I dont want to have to dump another 500-1000rds to get it where it is now. I'll likely have my reamer by then and the Shilen gets thrown on.