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Bullet deformation

7K views 40 replies 24 participants last post by  Bigbore 
#1 ·
Haven't experimented myself yet - but was wondering if the magazine/feeding system on a 10/22 rubs or deforms the nose of the bullet at all during cycling.
Just curious if you are going for the best accuracy - would you want to feed each round single shot?
 
#3 ·
do you mean feed each round into the chamber by hand?

if so...hand feeding a 10/22 is a challenge, at best...at least to me...:cool: but there is an attachment made to operate the 10/22 as a 'one shot'. it's a magnetic plate that attaches to the bot that prevents the bolt from blowing back during the shot cycle. you have to remove the attachment and operate the bolt manually to replenish with a new round. ebay did have them.
 
#6 ·
Short answer is YES

I have run lots of stuff through four different actions (I got curious after noticing damage on bullets run through the first 1022) and ALL of my rifles caused pretty consistent nicks, scrapes, and dents. Probably 80-90% of the rounds that I cycled showed what I would call "significant" surface damage to the exposed surface of the bullets.

This has held true with any and every brand of ammo and style of bullet that I tried.

I don't think the basic 1022 design was intended to be a "super" target gun and the feed system was probably tweaked more in the direction of reliability than immaculate operation.

And the comment about hand-feeding ammo, one-at-a-time, into the chamber of a 1022 is correct, I have found that it's pretty much a major PITA.
 
#12 ·
Funny this question came up right now. I compete in autoloading benchrest and have built quite a few competition guns over the last couple of years.

I have always tested guns by cycling a clip full of cartridges manually and examining them with a magnifier for bullet scrapes and nicks. I have never owned a gun that didn't nick or scrape the lead bullet to some extent, even though functioning reliably. This has to affect the gun at some level, but I have observed this even on my most accurate rifles. Might add that I chamber for particular bullet lines.

I was going to shoot my factory class 10/22 the other day and decided to try and tune it up. I hadn't shot it much but it was a decently competitive rifle and functioned smoothly. When I first set it up, I used a pretty tight chambering.

I had put the gun together originally with a tight chamber and a tenon length of .0.715. I had since proved to myself that the tenon really needs to be set at the spec of .745, or ignition is affected, so I set the shoulder forward 0.030 and went shooting.

It shot very well, but I had over a 50% failure rate of properly seating the bullet. It was a nightmare of a match, but I won.

The next day, I decided to try and fix it. I intended to try modifying the chamber bevel, change recoil spring tension etc. My best guess was that the chamber bevel/base diameter area was causing the problem due to the barrel face being closer to the clip feed ramp.

Before doing anything else, I decided to substitute a bolt from an unlimited gun. Lo and behold, it ran through the entire clip without a hitch. I tried several clips of several styles including hi-caps which have always caused trouble. Perfect feeding. I then ran the scrape and shave test and got not one visible mark in 50 rounds through several different magazines. I am now waiting for the next match to see if this improved feeding equates to improved accuracy.

I once watched a shooter at another club shoot a test target with his Beretta autoloader from the 60's. He is a good shooter and the gun is competitive in the factory class. He single loaded into the chamber and shot a test target which at the time would have been the highest score ever shot with a factory class rifle and would win more than 95% of unlimited matches. It was 10% higher than his normal winning factory scores, and that was in a rifle that generally feeds better than a 10/22.

My point in all this is that feeding and accuracy in an autoloader is a complex issue, with many interrelated issues. Changing one thing often requires a change in another area that was working well previously.

I will say that, in an accurate rifle, bullet marks and deformation can hurt accuracy and can be caused by bad feeding. However, this is often not obvious or even important in a rifle built for reliability and function, since it will never exhibit accuracy at a level that will be influenced by these small changes.

ABRA has progressed in just the last couple of years to the point that you need to post a couple of 196 or 197 cards in a match to have a good chance of winning. To put that in perspective, ABRA is sort of an all or nothing target where you have to touch a 1/2" circle to score a 9 but you must touch a 1/8" dot to score a 10. To score a 197, you can only miss a 1/8" dot 3 times out of 20 at 50 yards. At that level of precision, the slightest influence can cost you a match.
 
#13 ·
i know its an older thread, but this has been a thing on my mind for a while now, and after a little research I found this thread, just figured I might do a little testing on accuracy results and see how much of a difference their is. I plan to use Center x for this and have decided to cut, scrape, and dent a box of Center x:eek: and compare those to a box of pretty ones, each round will be hand feed using a forceps for getting the round into the chamber easier. I will use the same lot # ammo and shoot groups of 5 rounds 3 times, then shoot a good round, cut round, good round, cut round, you get the point. Will post results next week.

Carl
 
#15 ·
not at all, just want to know if there is a difference between a dented, cut, scraped bullet compared to one that is not, after all most 10/22 do leave some kind of deformation on the bullet when putting the round into the chamber, I have checked all 3 of my 10/22 and each one leaves a small scrape or cut on the bullet when going into the chamber, now this is not much of a cut or scrape and you need to look pretty good to find them but they are there. Kidd, GM, and Ruger barrels, just want to know if this makes a difference in accuracy.

Carl
 
#28 ·
I am not expecting much if any change in impact over a good round, but we shall see.

Carl
The pellet deformations did not show much deviation but pellets are a different design(shuttlecock) so they are not an apples to apples comparison.

Do you have high speed video equipment? I have a Casio high speed camera and plan to do some bullet flight video when I get more time.
 
#18 ·
I am real interested in seeing what your testing shows. I recently built up a 10/22 based on Kidd parts, but with a Shilen barrel. Initial firing showed bullet tip distortion due to the top of the bullet hitting the upper portion of the chamber in the barrel. Found that one of the four OEM magazines was worse than the others. Spring tension adjustment of that mag. helped, but still not as good as the others. What obviously happens is that the cartridge is cocked as it enters the barrel. On my rifle I found that the sharp edge of the extractor was not allowing the cartridge rim to ease-up along the bolt face as the cartridge is fed from the mag. I also used a special rubber/abrasive polishing buff in a Dremel to gently polish the cartridge recess on the bolt face to a high luster. This really helped!
Aside from the bullet mangling issue, what I found happens with some regularity is that the bullet loosens in the case after feeding into the barrel (due to cocking forces during chambering), this may be more troublesome than bullet tip deformation.
 
#19 ·
Stockcrafter, funny you mention that because I also checked for looseness of the bullets when inspecting for damage, but did not find any loose ones, my next step is to polish the mags and check results, should be a fun next 4 days as alot of Center x and CCI sv will be put down range. Will post results next week.

Hope everyone has a great Easter weekend.

Carl
 
#21 ·
Curious of your upcoming results

I have a Kidd supergrade that was shaving bullets on feeding. Polishing the chamfer on chamber lead in stopped that. But get a nice crescent shaped dent on feeding with some ammo where it used to shave. Other ammo not so much. Changing ammo isnt a practical option these days. A new barrel is cheaper than 2-3 bricks of ammo.

I might give a try to polish on the bolt face recess and smooth the extractor edges. I have a black bolt and noticed brass colored wipes in the recess. So there is some friction going on there. Will take a a few weeks to get to it for me. Matches coming up and dont want to break down gun to do that right now.
 
#22 ·
I have a Kidd supergrade that was shaving bullets on feeding. Polishing the chamfer on chamber lead in stopped that. But get a nice crescent shaped dent on feeding with some ammo where it used to shave. Other ammo not so much. Changing ammo isnt a practical option these days. A new barrel is cheaper than 2-3 bricks of ammo.

I might give a try to polish on the bolt face recess and smooth the extractor edges. I have a black bolt and noticed brass colored wipes in the recess. So there is some friction going on there. Will take a a few weeks to get to it for me. Matches coming up and dont want to break down gun to do that right now.
I think I should clarify what I did to the extractor. If you look closely at a Ruger production extractor you will see that the bottom edge (closest to the magazine), is slightly rounded. This is what is referred to as a 'die-roll' edge in metal stamping vernacular, and is a natural part of most stamped metal parts. On the Kidd extractor there is no die-roll. The edges both top & bottom are sharp. So, what I did was to form a polished radius using a Dremel mounted with a rubber/abrasive wheel to simulate the missing die-roll. Ballpark radius size is about bottom 1/3 of extractor width. This allowed a much easier transition of the cartridge into the bolt face cartridge rim recess. Upper 2/3 of extractor width remains sharp so that extraction is not affected.
 
#23 ·
My amateur-hour thinking would be that nicks and scrapes along the side of the bullet would not matter since those surfaces get squished and deformed into the rifling anyway, so who cares? As long as the bullet is not losing mass in the process, that is.

All we should care about would be the portion of the bullet not in contact with the rifling (the nose).

Is that correct?
 
#26 ·
My amateur-hour thinking would be that nicks and scrapes along the side of the bullet would not matter since those surfaces get squished and deformed into the rifling anyway, so who cares? As long as the bullet is not losing mass in the process, that is.

All we should care about would be the portion of the bullet not in contact with the rifling (the nose).

Is that correct?
From my understanding, defects in the drive band are impactful to accuracy. The gouge i get is about 1/32" deep crescent and no ammo which gets this in my gun shoots well at 100 yards. The problem now days is finding different ammo. I have a few cases that gouge and group about 1.75 inch groups at 100 yards. Before the ammo shortage i could be picky and keeping just about an inch at 100 yards was a practical goal. The same ammo that does about an inch but didn't gouge. Maybe softer lead in new batches. Whatever the reason, The newest lots gouge out and groups are worse for me. It matters since that will drop points in matches.

In any case, no gouge wont' hurt. So that's what i would like to do and gives me a reason to play.
 
#27 ·
Interesting comments on bullet deformation. I have not tested my Kidd yet. . But I was seeing it happen in a model 41 pistol . After some experimentation, I determined that if I chambered a round, and extracted it without the magazine in the gun, I had no deformation. If I left a magazine in the gun and then extracted it, I saw deformation.

Conclusion : on my 41, very little if any deformation occurred by chambering. The damage happened when the round was extracted with a magazine still in the gun .

I just tested my Finnfire P94s. Same thing.

I’m not sure I understand it, but I’m pretty sure on both guns, the deformation is happening when I extract the round .

Has anyone else experienced this ?
 
#29 ·
Will post some pics this week , but spent Friday sending bullets down range and after firing 50 that i deformed myself that were hand feed, 50 un deformed hand feed and 50 feed through the mag there seems to be no difference in accuracy, with the mag feed ammo having the better groups, just slightly better and needed to measure to know for sure. So after all that I guess the bad shots are my fault:D

Carl
 
#30 ·
Well, I just tested both of my Kidd rifles . Both put a crescent shaped dent in the bullet when the bullet is chambered . Even so they both shoot ridiculously good .

However, my SAKO P94S does not distort the bullet that I can see . It is crazy accurate and will beat the Kidd every day.

So my conclusion is it might make a difference. But the difference ain’t a lot .

Thanks for posting this thread. I’d have gone all ocd if I thought my rifles were abnormal !
 
#35 ·
Well, I just tested both of my Kidd rifles . Both put a crescent shaped dent in the bullet when the bullet is chambered . Even so they both shoot ridiculously good .

However, my SAKO P94S does not distort the bullet that I can see . It is crazy accurate and will beat the Kidd every day.

So my conclusion is it might make a difference. But the difference ain't a lot .

Thanks for posting this thread. I'd have gone all ocd if I thought my rifles were abnormal !
I called Kidd yesterday and sent them pictures . They asked me to test every mag. I did . All bullets were deformed after feeding .

Upon closer examination , the magazines were a bit dirty so I decided I'd clean one and try it again . Before cleaning, every round in the mag was dented after chambering. After cleaning 7 out of 10 had no deformation that I could see . The last 3 in the magazine had problems . I increased spring tension on the magazine and it has passed one round of testing. More testing is needed though to see if I've eliminated it completely.

The magazines were not all that dirty in my opinion , but apparently a little build up can make a very big difference .

This is the kind of damage I was getting before working the mags over:

There were some other magazines and some were better , some worse .
 

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#32 ·
not according to what I seen, at least out of my 10/22, now granted these bullets that I deformed weren't deformed real bad but about the same as if they were ejected into the chamber from the mag and after all shots were taken you could not tell a difference at 50 yards, and as stated the best 10 shot group came from a mag fed 10 shot group. I do agree that if the bullet had more damage to it that it would affect accuracy, just as in the video a few posts back.

Carl
 
#33 · (Edited)
A lot of years ago, a gun magazine that I purchased regularly ran an article on just this subject; can't remember the CF caliber they chose (probably .308 or 30-06), but the results were interesting. Can't remember all they did to deform groups of bullets they shot, but I do remember that the least hit on group size was when they deformed the bullet tip by bending it a bit off the natural center line, while the biggest degradation of accuracy occurred when they took a small drill (can't remember the diameter) and went back on the parallel mid-body of the bullet and drilled a hole through the jacked (and maybe a bit into the core - again, my memory fails me, as it was published 35+/- years or so ago). So the biggest negative effect on accuracy was with "damage" that altered the balance of the rotating weight of the bullet in flight by making one portion lighter than the rest, throwing it considerable out of balance in the rotating direction. Just some food for thought that may shed a bit of light on some portions of this discussion.
 
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