What can a reasonably good shooter expect from a reasonably good rifle with reasonably good peep sights expect within reason of course as a reasonably good group? Or, how will I know when I've "maxed out" the accuracy of my 32-40 plain base iron sighted rifle? It is not drilled and tapped for a scope. I'm doing 2" @ 100yds right now when I'm shooting well.
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Are you breech seating or shooting fixed ammo? Wt. of your PB bullet and twist rate for your bbl. Does your rifle have a set trigger ?What powder and charge are you using. What is your SS rifle? Need some basic and we can work from there to get you to nice small groups. Shoot mostly SS rifles and PB bullets, be more than glad to help out.
What I'm after is a "rule of thumb"for iron sighted target rifles that are iron sighted versus scope sighted. In other words, if I'm shooting 2" regularly, is that about all I can expect.? Not just a single specfic instance. One inch seems to be a bench mark for scoped rifles. What will that rifle do with peep sights and the same shooter?
Iron sight groups about 1.6 times scope sight groups, based on 22 rf 50 yard group sizes.
Iron sight groups require proper-sized bulls.
Perhaps my standards are low, but 2" 100 yard groups with open or aperture sights sound good. As stated above, however, the target shape and bull size should be optimum for the shooter. This will likely vary from one shooter to another and it's worth experimenting.
Again I assume your rifle is a SS 32/40 and you are shooting breech seated bullets. There are shooters with these rifles that can shoot just as good groups with IS as scopes. Do not get in a hurry, it all takes time to get where you are headed. It is amazing what can be done with a SS rifle, and you definitely have the right cartridge in the 32/40. I know you are looking for a specific group size, but again time and practice and being a good "student". Can your 32/40 with IS shoot, lets say shoot 1" groups at 100 yds, yes. With right conditions and proper load work up it can be done, and not one of those things that are a rarity. You will find that people have lots of theories in this shooting sport. Listen to those that have the voice of experience and have tried results to share with you that can be an encouragement to getting the most out of your equipment and enjoyment. Many times the true limiting factor in what a rifle will do is the shooter, not the rifle. Just part of the game is our own attitude, set up, reading conditions, one can go on and on. There is so much involved, but that is what I find so fascinating about cast bullet shooting.
Be glad to pm you more on this. Do not let the naysayers influence you. Have a great day and wishing you and yours a blessed Christmas.
Excellent reply GWarden
There are two single shots here, a 32-40 and a 38-55. Both are fully capable of putting five easily within an inch at 100 with PB, scope or irons. If the shooter is up to it.
I visited with an accomplished long time shooter/gunsmith, whose name we would all recognize, at the CBA military nat. tournament a couple of years ago about this same topic. He went as far as to say that if the bullseye is sized right for the sight aperture, aperture sights can shoot just as accurately as a scope.
50 yard benchrest, 22 rimfire, 5-shot groups, average group size/# of groups
Mossberg 44US Irons .830”/106, Scope .600”/54, .830/.600 = 1.384
Remington 513T Irons .796”/62, Scope .490”/225, .796/.490 = 1.624
BSA 12/15 Irons .837”/60, Scope .470”/450, .837/.470 =1.783
The average of 1.783, 1.624 and 1.384 is 1.597.
Iron sight groups are about 1.6 times the size of Scope sight groups.
1” iron sight 100 yard 5-shot groups? 1? sure. Average for 5 groups? Somewhere between unlikely and mythical.
joe b. (Sorry if the data impinges on opinion.)
A long time ago, I watched a fellow, that had his grand daughter with him, shoot under 0.30" groups after a match. He invited all of us to shoot his rifle. His rifle was a single shot falling block type rifle in 32-40. He breech seated his bullets and gave us the why and wherefore of how to load it correctly. We all did a little worse, but we all shot under 1/2" at 100 yards. The load and how you load it are VERY IMPORTANT. If yours is well put together, it should shoot a lot better than what you're getting. My first suggestion is soften your alloy.... One to thirty tin/lead alloy or softer and try again. A very low viscosity lube will also help.
On the iron versus scope....Harvey Donaldson wrote on that in his book "Yours Truly" about that. Set up properly and used correctly... basically little difference in group size. How you do things and what you pick is extremely important to what you get.
.... back when the world was not quite so blurry ... i shot 4 position iron sight 22 competitively ... i found the cost of the peep sights was not as important as having a very black bull and very bright lights on the targets. i did select a front aperture depending on the range.conditions. usually a translucent amber disk worked the best.
..and always for me, eye strain along about 30 shots out of the 40 was a factor .. maybe ( another ) one of the advantages of a focus-adjusted scope sight.
weirdly, after some 60 years, i still can visualize the sight picture required so the gun could fire ... funny that i can't remember how to do high order differential equations though ... ( g ) ...
Factors Of Sighting Error
Benchrest shooters have moved to 36 X telescopic sights and sometimes scopes with even higher power. We know (or think we know) that using high powered telescopic sights allows us to shoot smaller groups than when using iron sights. But, and there's almost always a but-there is some suggestion that iron sights can be used to shoot some very small groups.
At the Old Colony Sportsman's Association in Pembroke, MA, there is a Winter League Match shot every Sunday from November to March at 200 yards, offhand, at the military 200-yard target, from a heated shooting house. The black is 13", 10 ring is 7" and the X ring is 3". The categories are Iron Sights, Any Sights, Howes (10# rifle, 3# trigger, flat butt), Over 40 Caliber, Rimfire and Single Shot Rifle. The best target of each category is hung on the wall, so that at any time one may compare the best scores shot with, for example, Irons and Any Sights. By Christmas the scores are in the middle 190's. I have been surprised to see that the Iron Sights categories do not lag the Any Sight = Scope categories by much; sometimes not at all.
In the ASSRA matches, I believe that it was Dick Hughes that shot the first 250 at 200 yards with Iron Sights a few years ago. The 25 ring on the German Ring target is 1 3/4". Several other 250 scores have been shot since. I remember watching Jerry Ventura shoot the first record 250 with a scope on a Model 44 Stevens at Western New York/Alabama Hunt Club, maybe a dozen years ago. So, the Irons aren't a great handicap.
And as a last example; I have found that I can shoot surprisingly small bench 100-yard groups with a good peep rear sight and an aperture-or even sometimes a leaf-front.
So-what effect do sights have on potential accuracy?
In the American Rifleman, April 1977, there is the article titled "Factors of Sighting Error" by L.F. Moore that describes the results of testing conducted at Aberdeen Proving Ground with various sights and conditions. I've read this article many times since 1977, and consider the results very interesting and the article virtually incomprehensible. Since the work was done at Aberdeen, at Government expense, I feel no qualms about using the data from that article.
The test was designed to measure the dispersion about the center of the target with various sights.
The tests were done with the sights/rifles in a machine rest, a target at 100 yards that was moved with a synchro-torque transmitter-receiver system, an electrical spark system that marked the target paper on command, and several shooters. The target was moved out of alignment with the sights, the shooter looked through the sight and aligned the target with the sight using knobs for up down and left-right and pressed a button that burned a small hole in the target. This was repeated for a series of "shots", the burned holes in the target forming a "group". These groups were measured and the Mean Radius (MR) was calculated and graphs were constructed using the MR data.
I interpolated the MR data from the graphs in the article. Since MR doesn’t mean much to me, the MR values were turned back into 5 shot 100-yard group sizes that I am familiar with. Jeroen Hogema of the Netherlands found, through some terrifying statistical analyses, that for 5 shot groups, group size = 2.5 X MR, so groups averaging 1" MR would have a group size of 2.5". Thanks again, Jeroen.
The information that I think is of particular interest is shown here in tabular form. The test identification numbers (Test # 7) are from the original article.
Notes on these tests:
Test 2, "Effect of Size of Front Sight Aperture on Dispersion" Rear Sight .046" aperture
Test 3, "Effect of Diameter of Rear Sight Aperture and Dispersion” Front sight .125" aperture.
Test 5, "Effect of Location of Rear Sight and Dispersion".
Rear sight aperture varied to suit, front sight .125" aperture
Test 6, "Effect of Location of Front Sight on Dispersion" Rear sight .042" aperture, front sight 13 MOA aperture. Note that this test measures the effect of the distance between sights on dispersion. After 25", which with 2” from rear sight to eye leaves 23” between sights, the reduction in dispersion is minor.
Test 7, Effectiveness of Various Types of Sights
First Telescopic sights; then the M1, M14, M760 and M2 Carbine sights are aperture rear and post/bead front; the M94, M70, M99 and M760 are "open" sights, and the M12 had a shotgun bead front only.
The other tests:
Test 1 "Effect of Learning on Dispersion" showed that dispersion was reduced as the number of trials increased. But not much, from .312" group diameter at the first try, down to .15" group diameter after 40 tries.
Test 4 "Effect of Target Type On Dispersion" showed dispersion varying from .15" group diameter on the NRA Smallbore Rifle Target to .375" group diameter on the "Game" target; with .042" aperture rear and .125" aperture front - 34" between sights.
Test 8 "Effect Of Illumination On Dispersion" showed that in almost-darkness, with an M1 rifle, dispersion is large - about 1.5" group diameter; and with a 2.5 X telescope it is only .325" group diameter. Given some light, from about 2 candles per square foot to 30 candles per square foot, The M1 rifle dispersion is about .55"-.675" group diameter, and the 2.5 X telescope dispersion is pretty flat at .175" group diameter.
This test shows that we can't aim very well in the dark, that with a little light we can aim pretty well, and that we can aim more precisely with a telescope than with iron sights. Few surprises.
Test 9 "Effect Of Target Type On Dispersion" First, with an M1 rifle, dispersion varied from .70" group diameter to .95" group diameter as target type varied from NRA Smallbore Rifle to "Game". Then, with an 8X Telescope, dispersion was .15" group diameter on the NRA Smallbore Rifle target, and .20" group diameter on the "Game" target. The author points out that "The smallest dispersion with match-type aperture front and rear sights was obtained with a round aiming point, approaching the small dispersion obtained on the same target with the 8X telescope, and actually surpassing the performance of the 2.5X telescope"
Test 10 showed no difference in dispersion as sight finish was changed on an M1 rifle-normal finish or no finish on the sights, then sights blackened with a carbide lamp, and then with a red translucent front sight.
Test 11 is hard to follow, but seems to show that tight fit between the stock and the shooter's face reduces dispersion.
Test 12 "Effect Of Mirage On Dispersion" shows dispersion varying from .075" group diameter with a 20X Lyman STS telescope to .175" group diameter in heavy mirage with target iron sights.
There are several factors affecting accuracy, and the relationship between these factors is slightly complex. Let's say that there are rifle, ammunition and sight factors affecting accuracy. Then group size is the square root of the sum of the squares of the dispersion due to these factors. For example:
with a perfect rifle and ammunition the sights would cause a 2" group
with a perfect rifle and sights the ammunition would cause a 2" group
with perfect sights and ammunition the rifle would cause a 2" group
Expected group size = the square root of (2"X2" ammunition) +(2"X2" rifle) +(2"X2" sights)
= the square root of (4+4+4) = 3.46"
Now let the sights error fall to zero. Expected group size = the square root of (4+4) = 2.82"
This, at least for me, isn't intuitive or expected, but it seems to be true. I first read it in Harold Vaughn's book, and have encountered this relationship several other places since.
I got my copy of the original article from Rudi Prusok, ASSRA archivist. He can supply copies.
The work on MR and group size done by Jeroen Hogema is too frightening for this article.
Thanks all. Collectively I think that answers it.. Yes it is SS BS RB 32-40. A real hoot to shoot. So much fun I never got serious about it, the fun got in the way bangin' gongs at 300 yds. Just want to know whats reasonable with iron sights.
One of the things I like about this forum is the excellent answers most questions receive. In this case from individual experience to the results of big buck scientific research -- all interesting and worthwhile. Thanks to all for taking the time to contribute.
Looking back over past years CBA postal single shot match #13, consist of 4/ 5 shot groups. Here are the results with scope, again agg of 4 groups, .587", .803", .727", .476", .551", .986", .453". That is for seven years, so it is not a fluke to get SS breech seated to shoot like this, and on a consistent basis when the conditions are good, or you are a great wind reader. I am afraid that we as shooters put the limit on what we think a rifle will do. Again when conditions are right at 200yds with scope I have seen five shot groups of less than 1", now that is not consistent, but it happens. Have seen on one occasion a shooter with IS, breech seating and this was with BP 5 shot group of .823. Again, I think many times we the shooter are the limiting factor. I remember in the past there was one really great military rifle shooter in the CBA matches, much of the credit to his success was his ability. I remember my shooting mentor telling me, lots of shooters try to buy success, it comes from the shooter developing his skills- a overlooked factor.
The answer that can be obtained consistently with IS at 100 yd is 1.25" or less . As ones skill level goes up groups will be seen to decrease in size.
Well, ya'all. I decided based on your replies that I could do better with my 32-40. Better accuracy was obtained with a 207 gr FN and 18 grn of 4227. I shot 1.5" today but it was only a single 5 shot group as I was trying several weights and charges.. One was a "flier" or it would have been brag worthy. So, now I know I can do better with iron sights and will pursue that.
First, Merry Christmas and Happy New Year.
Second, going back to original question on what is reasonable, here are my tcw. First, whatever beats my buddies so they buy the root beer. Second, a six inch circle at 200- yards being centered in the chest area of any game larger than a fox will take out any game shot at. So, for me a reasonable group for non-paper punching purposes takes out heart of caribou and keeps me from buying at the watering hole.
Now, as to maxing out accuracy, I will leave that to the responses above. I am still trying to consistently get under 2 inch groups from my trapdoors at 100 yards. Done on occasion, once a year or so under 1.5 inch, just not as consistent as I would like. Gives me reasons to get out to the range.
Hey, it has been enjoyable being part of the forum and I thank one and all.
Wishing all a good new year of shooting.
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