Tang sight Aperture size?

[JRD]

Just pulled out my Pedersoli Rolling Block in .45-70 after not shooting it for about 8 years. Went over it and got it nice and cleaned up, so loaded up some fresh ammo and headed for the range.

Here's the thing: I remember I used to be able to see through the aperture in the tang sight! I'm not that old, but I swear my eyes aren't as good as the used to be.

The aperture measures .027" dia. This was measured with a pin gage at work. It's a big eye cup that you get right up to, so it's supposed to be a small opening.

I've been thinking of having the wire room at work open the aperture to .050" or so and see if that's better for me. I don't want to go too big and loose some accuracy. I just want it to be big enough to see through clearly for me!

Anyone know of standard sizes that the fancy BPCR apertures are or what aperture size works for you?

Thanks,
Jason

[carpetman]

Jason--------You mention not being THAT old. Are you perhaps around 40? If so,and you dont already have bifocals/reading glasses,the smaller opening is helping with your problem. Whatever your age,you are now having difficulties that did not exist previously,first step might be an appointment with the eye dr. BTW if your problem is what I suspect,I'd go with progressive vs bifocals. I started with bifocals and went to progressive and like them better(many will cuss progressives). I was told if going to progressive first that the adjustment is easier than if you previously wore bifocals.

[wills]

Make sure the staff (or whatever that thing is called) is perfectly vertical and you are looking through the aperture at a right angle. If the staff is leaning slightly forward or back it can make a big difference.

AND

Get a Hadley eyecup so you can adjust for your light conditions. If you have good light you can use a smaller aperture, bad light will force you to a large aperture.

http://www.buffaloarms.com/browse.cfm/2,224.html


I wear bifocals ands they don’t help when shooting at 500 meters.

[Wayne Smith]

I would also get the adjustable arperture for your sight. It makes a big difference, because weather or not I can see through one or another depends on light conditions as much as my eyes.

I'm not disagreeing with Carpetman, I use progressives as well and like them. Get ye hence to thy optomotrist. I was dxed with gloucoma on the basis of the shape of my optic nerve exiting the back of my eye. I've never had pressures above 18! Thanks to God, and it was a miracle that I saw my wife's opthomologist rather than my optomotrist, it was caught early and stopped before I lost much sight. Now I take eye drops every morning and there has been no change for two years.

[4060MAY]

for BPCR I use an adjustable eyecup from Kermitool.
The fixed eyecup supplied with Browning sights are .040, .050, .060
with glasses on I use the .060 with front aperture that fits the target.
.100-.150 depending on light and distance.

[KCSO]

I sometimes have to change eye cups as the day wears on. As the light changes the size of the eycup needs to be changed too so yu get the sharpest focus on the front sight. That is why the Merit disk was so popular with the target folks in the olden days. I couldn't begin to use the eye cup that came with my Sharps rifle, I drilled mine out and ran it up to a #53 drill to get the sharpest focus on an average day. For hunting I use a 1/4" apreture.

[JRD]

Guys,
Thanks for all the replys. I think I will probably open up the aperture to .050 or .060" and live with whatever I get.

The Hadley eye cups look nice, but they will cost more than I paid for the sight. Since the gun will only be used for a plinker, I want to keep it on the cheap. If it were a serious BPCR rifle they look like the way to go.

The quality of the Pedersoli sight is only so so, but that's why it costs so much less than the high end sights.

There isn't a positive detent to keep the sight verticle. There is a sort of detent, but it allows the sight to flop. You need to keep the screw tight and line the sight vertically by eye. You can tell if it's verticle or not because tilt it a bit and I can no longer see through the aperture.

I'm not yet even 30 (still a kid), but am stuck with glasses. I don't need them for reading, just distance. I don't remember it being so hard to see through the sight last time. I ought to get an eye exam anyway. I was in college the last time I shot this rifle.

Jason

[Wayne Smith]

Pedersoli has a "hadley" type adjustable arperture for their sight, and it's not as expensive. I, too, have a Pedersoli long range sight.

Don't overlook light conditions as a cause. When in bright light I get glare and need a larger arperture. In the house, looking out the window, the smallest is fine.

[Blackwater]

WElcome to the world of fading and/or fuzzy eyesight! It's a big boat, and there are lots of us. The Hadley adj. eyecup, as mentioned, is the best choice on your BPCR, but FWIW, the Merit iris style aperture for Lyman and Williams peep sights is really neat. The iris works like a camera shutter, and goes from a pinhole to about .1". I have one on a sporterized '03 Springfield, and if the light's not too dim, I can actually hit something with it fairly well. It, along with the Hadleys, are as good a thing as can be had for eyes that ain't perkin' like they usta'. The Merit is still made, BTW, and as long as we can still shoot guns, and folks' eyes get fuzzy at around 40ish, I think there'll always be a need, and a constant demand for them.

[lovedogs]

Hadley's are nice if your wallet can stand it. Mine can't. I use a .050 aperture all the time and it works pretty good. When I get out past about 700 yds. it gets a bit fuzzy but on a clear day I do well out as far as I can shoot. My range here only goes to 876 yds.

[JRD]

Thanks for all the input guys. Here's what I did:

Opened the aperture to .052 (#55 drill). It works WAY better than at .027"! The lighting at my indoor range isn't the greatest, but I don't want to open it any more.

I also set the windage slide up on a surface plate and scribed some hash marks so I have a windage reference.

Lastly I made sure the tang sight was plumb from side to side.

I took it to the range last night with some Lyman 474191's that I cast a while back. 57 grains of IMR 3031 had them running about 1850 fps. They shot really nice. A few shots on paper to get the sight adjusted and then I knocked over some steel plates. I like it.

A question I have on my load though is that there is a lot of smoke left in the barrel after each shot. The smoke is very thick and yellowish-brown. There's also some partially burn powder kearnals left in the barrel.

I'm guessing the powder isn't burning efficiently. Maybe the bullet is too light. It's an almost fully filled case, and I'm crimping the bullets in tightly. (Good neck tension as well.)

I had worked up to this load. I started with the Lyman CB min load. I increased a few grains at a time until I got here. Starting load was only 1450 fps and cases were a little sooty. 54 grains was better. I like the 57 grains. I'm just curious as to the cause of the smoke and unburnt powder.

Jason

[lovedogs]

I'm confused JRD...'course that's not unusual. But my books don't show a 474191. Do you mean a 457191 for that .45-70? The Lyman 48th shows that bullet but only in their Springfield level loads. Can't give you a definate answer but can tell you how my .45-70 acts. Using 3031 and 4895 didn't work out. It acted like it was too slow of a burning rate. It shot okay but did like you said, left too much unburned. I'd say if it shoots okay, has small shot to shot variation in velocity, and isn't position sensitive then it's usable. What I found in mine is that velocity varied a lot from day to day and it was position sensitive. Like stated, I think it was too slow.

When I went to heavier bullet (500 gr.), Reloder 7, and mag primers then things got really good. It was no longer position sensitive and velocities only varied about 7 FPS. The real proof in the pudding was that it then performed out at long ranges. If a load isn't consistent you'll see it at long ranges. At 100 and 200 you may not see it, but past 600 and on out to a half mile (my range is only 876 yds.) you'll really see it.

For those light bullets I couldn't get them to work the way I wanted until I tried Accurate 5744. It leaves a trail down your barrel but if you look at the fouling the powder is actually burning, it's just dirty. Don't worry 'bout it though. I finally went to using the 5744 on all lead bullets I use in my .45-70. The velocities were good and it shot great. You don't need a filler to keep it in position and gone are the days of tipping the muzzle up to position the charge like we have to do with some of the low density powders.

Don't know what kind of shooting you're doing but I also haven't had much luck with those lighter bullets at long ranges. From 400 gr. and up usually stabilize way out there... past 600 yds. Some rifles won't stabilize light bullets too far. 'Course if you're only shooting short ranges then the light ones are fine... they kick less.

Good luck and God bless!

[JRD]

Lovedogs,
I had an attack of CRS. I did mean the 457191, the 300 grain Lyman.

I'm only using these loads for plinking and right now I'm playing in an indoor 100 yard range. I don't have to worry too much about wind. Lighting isn't OK, but is probably the cause of my not being able to see through the aperture to start with.

I'm going to stick with the 3031 load because I have enough on hand to burn up. The plates at 100 yards won't know the difference. If I ever get on a long range, then I'll need to rethink my approach.

I've also got some 457406 bullets cast up. (It's a 475 grain RNGC meant for 458 Win Mag. Let's hope I got the number right this time.) But it shoots OK out of my rifle. Last time I loaded some I used a compressed load of Accurate MRP. This gave about 1150 fps. Ken Waters listed a similar load in Pet Loads. It only works with heavy bullets. You get a lot of unburnt powder, but the pressure is probably at or below BP levels. 10 years ago one of the big distributors had the powder on sale really cheap, so my Dad bought 32 pounds of it. I don't mind leaving some of it unburnt. Next time I have the chrono set up, I'll have to check it's extreme spread.

Jason

[lovedogs]

Sounds like you're having fun and as long as you're safe and enjoying it, that's great!