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91/38 accuracy issue

Posted: Wed Aug 22, 2018 1:50 pm
by lamontagne0527
I am having some issues getting my 91/38 carbine to print on paper at 100m. I am using a 140gr hornady sst bullet over 30 grains of H335. Should i be aiming wicked low at 100m since the sights are calibrated for 160gr bullets? I'm puzzled with the sights since they are fixed at 300m battle range i believe. Im sure i will get it on paper sooner or later just hope it doesn't take 100 plus rounds to do so.

Re: 91/38 accuracy issue

Posted: Wed Aug 22, 2018 8:10 pm
by Rapidrob
1. Slug your bore.
2. Is it counter bored?
3. What is the true diameter of the ammo you are using.
Failure to check any of the above will cause accuracy problems.

Re: 91/38 accuracy issue

Posted: Wed Aug 22, 2018 8:16 pm
by lamontagne0527
Bore is a mystery since I haven't slugged it but a .264 bullet hardly enters the muzzle. It isn't counterbored and I'm using hornady. 264 140gr sst's

Re: 91/38 accuracy issue

Posted: Thu Aug 23, 2018 8:38 am
by OLDGUNNER
Hi – It sounds like you may be at a distinct handicap where you can’t get it on the paper. Are you using a range where one has to use a given bench and the closest paper has to set at this 100 meters? I would think that that would be an unnecessarily hard place to start in your case. There would be a dozen and one ways to get started. I could probable get you on your way but we should have to get you on the paper with ‘one’ shot, not a hundred. In other words get closer to the paper or bring the paper closer to you. And there is nothing wrong with a 100 foot distance or even less to start with. And that shooting where everyone has to stop and everyone checks their targets at the same time – that could drag you out for...a long time. Could you see a way to get out into some woods or a place to shoot all by yourself? And as far as getting it on the ‘paper’ where you are at, do you have any gift wrapping paper? Or is there some rule that you have to use some smaller piece of paper?

Re: 91/38 accuracy issue

Posted: Thu Aug 23, 2018 10:39 am
by nrobertb
Shoot it at 25 yards. If you can see a bullet hole that will tell you what is happening at 100 yards.

Re: 91/38 accuracy issue

Posted: Thu Aug 23, 2018 10:42 am
by lamontagne0527
alright, i will move the paper closer to see where the rounds are going and then take it from there

Re: 91/38 accuracy issue

Posted: Thu Aug 23, 2018 12:46 pm
by Rapidrob
How is the muzzle crown?

Re: 91/38 accuracy issue

Posted: Thu Aug 23, 2018 3:03 pm
by OLDGUNNER
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It’s funny you mention ‘counter bore’. Back 60 years ago when I was doing the Bubba job on a Carcano, a local gunsmith told me that he could do a counter bore on it if I would like. And I said why....And he said oh it might make it shoot better. I didn’t know anything about that so I said okay, and here is a picture of it. Now I didn’t know enough to do any checking ‘before and after’ so of course I would never know. But now I notice some chattering marks on his counter boring.

But I have a few Gunsmithing books that have articles on this and I understand such things as damaged crowns and so forth. One was where some guy made little dings at the edge of a bore for comparing any accuracy changes, but there were no pictures so who knows how big his ‘dings’ were . But the gist was as I remember, he had to ding away before he noticed any change, which I realize is meaningless. And I do remember one where some gunsmith said that he liked to counter bore .22’s like two inches for improved accuracy. Now I do not recall his rationale nor have I heard of that since and I also have no idea of the merits of such.

Another was, in general, one can clean up the crown of a barrel just for the heck-of-it by turning a bearing ball by hand or in a drill motor with some lapping compound, just to the point of seeing a slight new shiny surface. I guess this is in case it is not true. This may sound okay but I have never done it. I have a feeling that this is basically what you maybe talking about.

I have also read where some bench-rest shooters do this between barrel changes.

Is it by chance you are mentioning it because maybe Carcanos can be known for bad crowns?

Re: 91/38 accuracy issue

Posted: Thu Aug 23, 2018 3:34 pm
by lamontagne0527
Rapidrob wrote:
Thu Aug 23, 2018 12:46 pm
How is the muzzle crown?
The barrel crown seems to be perfectly fine, the rifle itself i believe is unrefurbished and was barely ever used in its service life since the barrel is nearly mirror bright, not bad for a 1941 91/38. I could always see if i can find some prvi 156gr bullets so the weight will be nearly the same as the 160gr surplus rounds.

Re: 91/38 accuracy issue

Posted: Thu Aug 23, 2018 6:52 pm
by OLDGUNNER
Well, my first gut feeling is that a lot of those had a reputation of having bores like .268 and .269...and a .264 bullet is not going to work worth a darn if yours is close to this case. If you can recall if you saw anything like a keyhole shot before in any paper you had, I would suspect this would be a thing to look into, irrespective of the weight. Like Rapidrob said, slug the barrel. You have other things to worry about before the weight. Now if you are not familiar with doing this, I would suggest getting it done by someone that is familiar with it....you may save yourself some time and trouble. But...but, let me retract that quickly...one learns more from their mistakes than their successes. I noticed when you said that the ‘bullet hardly went in’, and it wasn’t clear to me just what you meant by that. If you were saying that your .264 bullet ‘did’ go into the muzzle,with you just pushing it by hand, then I would say get the right sized bullet before going any further. This is just my opinion.

Re: 91/38 accuracy issue

Posted: Thu Aug 23, 2018 6:53 pm
by OLDGUNNER
I can't get this duplication deleted. Well, my first gut feeling is that a lot of those had a reputation of having bores like .268 and .269...and a .264 bullet is not going to work worth a darn if yours is close to this case. If you can recall if you saw anything like a keyhole shot before in any paper you had, I would suspect this would be a thing to look into, irrespective of the weight. Like Rapidrob said, slug the barrel. You have other things to worry about before the weight. Now if you are not familiar with doing this, I would suggest getting it done by someone that is familiar with it....you may save yourself some time and trouble. But...but, let me retract that quickly...one learns more from their mistakes than their successes. I noticed when you said that the ‘bullet hardly went in’, and it wasn’t clear to me just what you meant by that. If you were saying that your .264 bullet ‘did’ go into the muzzle,with you just pushing it by hand, then I would say get the right sized bullet before going any further. This is just my opinion.

Re: 91/38 accuracy issue

Posted: Thu Aug 23, 2018 10:01 pm
by les1234
How are you aligning the sights? The Italian system was to "bury" the front blade in the very bottom of the V-Notch. Not "all level across the top" like US shooters are used to doing. If you hold the top of the blade even with the top of the rear sight leaf, you will shoot over the top of the target. One option, just to get some groups on paper, might be to staple up 2 targets, a lower "aiming point" with a large sheet of paper above it to find where it's shooting. I have heard of people either making a taller front sight, or building it up with JB Weld to get the groups lower.

Re: 91/38 accuracy issue

Posted: Fri Aug 24, 2018 1:10 pm
by OLDGUNNER
Discussion is fine of course but I don’t think that there is reason for all of the concern and misunderstanding about the fixed sights on some rifles such as the Carcanos with their longer range battle sights, when it is so easy to just make a front sight for any range one may like with a little piece of nickel-silver and some ‘Silver Solder’. I just like the looks of the type in this picture..https://www.bing.com/images/search?q=Wi ... ORM=IDINTS.
the 11th one down. They are made to tap and screw on. But some may find tapping and screwing beyond their comfort zone, so just use the good epoxies of today which should be good enough. Boeing uses buckets of it to glue their Jet Liners together. And sure, one can just add a tad of epoxy and if it gets knocked off, put some on again...but one will just have to adjust every time.

Re: 91/38 accuracy issue

Posted: Fri Aug 24, 2018 6:50 pm
by Rapidrob
For my experience shooting the Carcano rifles over the last 50 years has been a real trial of tribulations. Bore diameter from year to year and even month to month can very a lot. Remember that many of these rifles were made by conscript labor conditions and they were also shot a lot in their lives.
I have seen bores as large as .267. No way a .264 bullet is going to shoot well. 99% of my rifles are .266. I have never seen a .264 bore in any Carcano.
The cut down rifles into carbines,such as yours are known for not shooting well. This being the "Gain-Twist" has been cut way back and the bullet is not being spun fast enough for accurate flight because of this.
Loads for Carcano's are critical. The bullet must fit the bore and the bullet must not be pushed too fast. I found 1,500 FPS seems to shoot the best at high altitude. ( 160 grain round nose flat base)
The sights have to be learned. You do not hold the sights as you do any other rifle. They are too large as well.
Stock fit/barrel pressure is a big deal. Try loosening/tightening the action screws to see it the group gets worse or much better.
I have not seen a boat-tailed bullet shoot well out of my rifles/carbines ( other than the 8mm)
After you slug your bore you will have a good starting point.Then you can work up a load that fits and should shoot well enough that you can check the other factors.

Re: 91/38 accuracy issue

Posted: Fri Aug 24, 2018 7:47 pm
by OLDGUNNER
Just something – I bought a wooden box of 1728, 7.35 ammo, dated 1939, for my two Carcanos in clips when I bought them. The bullets are steel jacketed with aluminum and lead cores and just with the sights as is I was shooting some 2.5 to 3 MOA groups, half and half. I shot maybe half of them and still have the rest, but the primers have deteriorated to be completely unreliable but the powder seems to still be good.
Both bores I measured at .300 to the nearest ????, say a quarter or half a thousandth....both real close to .300.