In my experience the rim of the round being fed scuffs the round below. That's why some shooters use single shot adapters.

It probably does affect accuracy some. I suppose it depends on how much accuracy you need. If you're shooting competition with match grade ammo you probably need to use an adapter to squeeze all the accuracy you can. If you're shooting squirrels, or plinking, at 20 yds with standard fodder a magazine is probably

 

Nifty, a new experiment to attempt.
Deliberately file a scuff on the face of a pristine round,
then insert into the chamber and determine if the orientation of the scuff
results in a trajectory change compared to an unscuffed round.
Sounds like another enjoyable morning at the range to me.

 

Oh boy, Jaia is off and running again. :dogrun:

 

A better experiment is to single feed 5 and then magazine feed five. It seemed to matter to me, but; how much seemed too vary. It was very measurable. You dont need an adapter just to do this experiment. Round can be flipped in with the finger.

I think what happens is feeding a round, the rim runs over the bullet as painter explained. First distortion. Then as the bolt extracts, the top of the bolt does a little scuff. I cannot say material is removed so much as pushed around, or bit of both. Mine was quite noticeable, perhaps this varies.

For short money, the single shot adapter is nice to have. I got the old Brno spring operated one. A quality item. That or plastic, I suggest you add one to you bag of tricks.

 

2 Boxes of SK Match, 1 lap file, 1 redneck test rest
and a half dozen test fire targets printed out.
Now if Joaquin stays way offshore, I'm ready to go.

 

Look at the underside of the bolt at the front. Chanced are it's rough and or sharp, and the bullet is getting scraped during extraction of the fired round. Breaking and slightly rounding the edge is the fix if that's the case. That's how you keep a Kimber from shaving the rounds. See pics:

 

Magazine Feed VS. Single Shot

Any magazine feed rifle will shave lead bullets as they feed into the chamber. That is why benchrest competition rifles are usually single shot.

In RBA Light Sporter Class, only magazine feed rifles are allowed to avoid the advantage of single shot and keep a level playing field. All other RBA classes have no such restriction and you will not see a magazine feed rifle on the line, ever.

When I bought my 452 American, I bought three ten shot magazines and one five shot magazine with it. I also bought the factory single shot adapter in the package deal. When ever I am shooting from a bench (not in formal competition) I always use the single shot adapter. When shooting from my Field Pod or prone with a bipod, I use the magazines. I like being able to load up 35 rounds at a time and shoot for a half hour before needing to reload.*

*As some of you may know, on the BRC and Ruger Forums, I am "Slowshot".

 

452 .22LR LH American

I use the 5 round metal clips and checked this 3 years ago and no markings. But thank you for the reminder as plan to go to our indoor range tomorrow to sight in at 50feet for winter paper practice. Things can change over time or 15,000 rounds. :bthumb: And I changed Ammo this past year!

 

I use the 5 round metal clips and checked this 3 years ago and no markings. But thank you for the reminder as plan to go to our indoor range tomorrow to sight in at 50feet for winter paper practice. Things can change over time or 15,000 rounds. :bthumb: And I changed Ammo this past year!

I still use the same two original metal clips and checked yesterday afternoon at our indoor range to sight in for 50 foot indoor winter paper practice. Ammo is feeding wonderfully with no shaving issues in my .22LR, 452 American. Nice heads up thread and worth checking. Nice reminder too, as I need to purchase 2 more 5 round metal clips as back-up.

 

Dang, thanks guys! I just bought a 455 Ultra Lux (with 10 round mag), then immediately turned around and ordered two five round mags and a single shot adapter. After I placed the order I started wondering why I spent the extra $20, but now I'm glad I did.

In order to increase participation the match director for our local big bore silhouette matches has added a rimfire tactical course with tin can sized targets at 25, 50, 75, and 100 yards. Last month there was talk of expanding that out to 200 yards. I'm definitely going to get some use out of that adapter.

 

I know this is an extremely relative question, but how much would that small amount of scraping translate to as far as shot dispersion on the target? Do you think in the neighborhood of 1/4" at 50 yds?

 

In my 453 American, that is a good number. I had reported more, but certainly that much for me. The thing is, shooting all day my groups will vary by more than that. It means going home and measure all the groups and average those results. Maybe 50 shots with, and 50 more shots with out adapter. But to call my 453 a 1 moa shooter (1/2 " at 50) on average, I had to go to a single shot adapter. And for me any more testing is a waste of over priced ammo. I should stone the underside of my bolt. That is a good suggestion, although a non issue going single shot.

The rim fire magnums use jacket bullets, no problems. Many more claims of 1moa for magnum shooters. I am sure there are more reasons, such as better bullets flying better, but with accuracy, IMHO, everything matters.

I know others on this forum are out shooting me. I find 22lr accuracy a challenge. I dont need any more doubts or issues in the back of my mind when a shot goes a stray.

 

Not the best day to test scuffed rounds, but beats watchin' tv.
WNW wind (from my 8 o'clock) at 11 gusting to 16 mph.
455 American with Lilja sporter barrel, bipod and bags, 50 yards, SK Match.

Filed a scuff on the leading face to change the aerodynamics
Scuffed round and unscuffed for comparison

Prepped and fired 10 rounds per target,
orienting the scuff at the 12, 3, 6 and 9 position in the chamber.

The results, top left target has scuff at 12 o'clock
top right has scuff at 3 o'clock, bottom left scuff at the 6 position
and bottom right is the 9 o'clock grouping.
Bottom center target was out of the box rounds,
10 warm up shots and the 10 final shots for comparison.

My conclusion?
Wind and muzzle velocity have more effect than a ding on the round face.

 

Scuff + crimping damage

My conclusion?
Wind and muzzle velocity have more effect than a ding on the round face.

Interesting test, thanks:bthumb:

I have (ehm.. I always had) similar problems on an old semiauto. In addition to scuffs there is that the crimping gets shocked and retrieving a round from the chamber you find that the ball has noticeable play with respect to the brass.
This because the round when chambered interferes with the upper chamber lip-you're unable to load a round slowly cicling the bolt.

Do you think this could affect accuracy ?

 

BH ,I would be my opinion that the loose nature of the chamber of he simi auto has more effect on accuracy than an occasional errant cycle problem.

 

2 ring grooves at the bottom of the lead/bullet

Next time I'll file off the driving bands on one side.
Spend another hour seeing what effect that has.
I'm so easily entertained, especially when I don't know the answer.

 

This post struck my interest yesterday . Last night I loaded up 3 five round mags with some wolf match and put one in each of my three CZ's. A 452 American , 452 Varmint and 455 Varmint and cycled five unfired rounds thru each . The American does put a good nick in the lead but it has always been an accurate shooter I guess I will start looking for rough edges on the bolt . The two Varmints leave a fine scratch on the lead that is barley visible . The best groups I have ever shot thru the Varmints from a good bench set up were using a single shot adapter but not much better than using a magazine . AS already stated conditions and shooter on a given day play a bigger role in my opinion . I shoot for fun against my buddies and that is as serious as I get .

 

The best groups I have ever shot thru the Varmints from a good bench set up were using a single shot adapter but not much better than using a magazine . AS already stated conditions and shooter on a given day play a bigger role in my opinion . I shoot for fun against my buddies and that is as serious as I get .

That ,"not much better," hardly matters in the real world, unless you are shooting organized competition Benchrest. Then it can be the difference between finishing first and finishing last.

As a result, I always use the single shot adapter on the bench, if allowed by the rules, and magazines at all other times.

 

This is not a definitive enough test to extrapolate to anyone else, but I shoot just as poorly with a single shot adapter as I do with a 5 round magazine.

 

Agreed, a real test would need hundreds of rounds fired in measurable groups with precise measurements taken and no changes in conditions. That testing has already been done at many competitions over the past 100 years or so. In BR competition hundredths or even thousandths of inches matter. As a result of those decades of testing, you will never see a magazine feed rifle on the line at any organized BR competition, unless the rules require a magazine.

If shooting at squirrels, crows or any other casual target, there will likely be no noticeable difference in the results with or without a magazine. Differences in those arenas are mostly due to the quality of the rifle, ammunition, sights or scope and ability of the shooter.

I am happy to shoot an inch at 50 yards with my CZ 452 American, with a magazine and a bipod. As the guy at my home club once said, "each of those shots would be a head shot on a squirrel."

None of my competition rifles cost me $6.500. My $800 Anschutz MPR, $700 Remington 37and $900 Martini International MK II have all been my most accurate rimfire rifles. Only the MPR had a magazine and I always shot it with a single shot adapter. The MPR gave my best ever RBA score (248/10X). My Rem. 37 gave my best ever 5-shot, 50 yard group (.125"). My Martini MK II is the most accurate iron sights rifle I have ever fired.

Now that being said, I shoot my CZ 452 American more than all of the others combined.

 

I had an extreme case of bullet shaving on my 2012 452 American that I picked up NIB last winter. I was able to significantly reduce it by:
1) carefully removing burrs from the radius as indicated on the first picture and 2) carefully stoning and polishing the radius and the bottom of the bolt to remove all machine marks (second picture).
As a side benefit, the stoning and polishing of the bottom of the bolt reduces friction between the sear and the bolt. I have given this "treatment" to 4 of my bolt action CZs.
If you decide to give this a try, just take your time and test the function of the bolt and magazine often to verify that you are decreasing the amount of bullet shaving as you are removing material from the bolt.