Shooting unreasonably high
- Thread starter Erickson5006
- Start date
I read 5".....my bad
You're not alone, so did I.
- Location
- Vancouver Island
I think most people would assume 5 inches initially as well - 5 feet is a lot of vertical to explain at 200 yards - especially if it's shooting high!
- Location
- Western Manitoba
Doing some quick math on scribble sheet - if your distance between your front and rear sight is 24", then you need the front sight to be 0.200" taller, to correct to "on" from 5 feet high at 200 yards (60 inches high at 7,200 inches distance). That is assuming the centre of your 200 yard group is 5 feet above your aiming point. Can not really do much, until you can say what your 3 to 5 shot groups look like.
Erickson5006
Regular
- Location
- Bonnyville Alberta
The local welder brought my sight from 0.78" tall up to 1.18" tall, and then I was hitting under a target at 25 yards. Im surprised by how extreme the changes are when you mess with the front sight.
But yeah, initially I was aiming underneath a 36" gong and hitting the trees above it
But yeah, initially I was aiming underneath a 36" gong and hitting the trees above it
You had a front sight welded??? I think that welder is a very talented individual. Most good welders are very artistic.
Now, it just means that your sight is to high and you will need to do some very careful work with a fine file, to get the height and profile correct, so that you can actually use that very decent rear sight's elevation adjustments.
If it were my rifle, I would file the sight so that its point of impact is dead on at 100 yards, with the lowest setting on the rear sight. That will give you plenty of elevation adjustment.
I did a bunch of load development for Tom Higginson, the orignal owner of Higginson's Powder, when it was called Ammo Mart.
The rifle he wanted me to give him data for was the Ag42B. That was back in 1974. The powder was surplus bofors made #44, which was very similar to IMR3031, depending on which lot he sent.
He sent me three different lots of #44 powder and they were all noticeably different from each other, as well as being quite fast for the 6.5x55. Almost to fast. That was the powder the Swedes used to load their cartridges though and Tom had several tons of it.
It definitely wasn't cannister grade, so I dumped 21 pounds of it into a five gallon metal pail, with a lid on it and mixed it thoroughly by rolling it across the lawn and upending it several times. No more worries about consistency. You will likely be using modern cannister powder, which usually have very consistent burn rates from lot to lot.
The reason I'm mentioning this is the Ag42B is a sensitive beast. It has a very narrow pressure range that it operates reliably in.
The loads need to develop at least 43,000PSI and develop at least 2400fps, with 140grn bullets for the rifle to function properly/reliably.
IMR4064 is just a tad slower than IMR3031 and can be a bit more forgiving, as well as being a better overall choice than IMR3031. Slower powders, such as RL19-22 are OK for bolt action rifles but the Ag42B needs faster powders, just like the M1 Garands love IMR4895 and for the same reason.
Cartridges for the Ag42B should not be loaded above 46,000 psi. They are very well built but the tech of the day left them vulnerable to all sorts of issues. There was a very good reason, each of these rifles was issued with a small parts kit, consisting of firing pin tips, extractors/springs with plungers, firing pin springs and a firing pin extrusion gage.
When these rifles are loaded to hot, they have a nasty tendency to break/throw springs, plungers, extractors and break firing pin tips. This can also lead to firing out of battery, with nasty results.
After my findings, some from reading up on the rifles in books, we didn't have the internet back then (dark ages) Tom took the several tons of that powder and had them blended together, he wanted a set of loading tables for the bullets, cases he provided me with, that the people buying his components and powder didn't have to be concerned with different lots. Especially as different as his surplus lots were.
I sent him 50 cartridges of each start/max bullet a load was developed for, as he wanted to send them to White Labs for pressure testing. Whether he actually did or not, I don't know.
The sweet spot for the three rifles I used with 36 grains of #44 powder(IMR3031) was right at 2400 fps with 140 grain bullets. This load gave repeatable one moa groups out of all three rifles.
The sweet spot for the 168 grain Hornady Match bullets was 37 grains of #44(IMR3031) at 2200 fps.
All loads used Standard Large Rifle primers. That was at Tom's request.
For my personal loads I used Magnum Large Rifle primers.
If you want consistent accuracy out of your rifle, which is capable of one moa, if the bore is excellent, then use a powder such as IMR4895 or IMR064.
If you're going to use slower powders you may sacrifice accuracy.
Also, make sure you have the rear sight drum set for the 140 grain load. It's a very simple switch. Google is your friend for videos to show you how.
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