Point of impact and recoil relationship in SMLE question.

[Jessegreenwood]

So, I am finding interesting things with my smle sight settings to get point of aim and point of impact together.
The thing I think is happening in the amount of upflip caused by recoil greatly effects point of impact.

Factory federal 175gr; the site needs to be set to 450
Realoads with 175 over 38 grains imr4895 the sight needs to be set to 200 yards
I have also heard of 150gr shooting lower than 175, which contradicts what velocity would suggest.
My thought, the more recoil, the higher the point of impact, and this suggests a few things
Military ammo probably has more recoil than factory, either loaded hot or cordite is really fast.
I can probably get close to that with imr 4895 if I load hotter, but I don’t really want to push my hunting load, for better brass life.
I would like to get reloads that match the factory point of impact, so I am thinking a slower powder?
If I can find in I am thinking h4350?

I would like to scope it so if I can match factory loads with my main reload, that would be ideal.
I would also like to set up other types of reload with near same poi, but that may be a stretch.

Any advice would be appreciated.
Thank you.

 

[Potashminer]

I suspect that you might want to read up on the "compensation" phenomenon that was used/discovered in the No.1 SMLE - a faster bullet exits at a lower trajectory than does a slower bullet - is to do with the oscillation of the muzzle, barrel time, barrel vibrations, etc. Totally amazes me that this was all figured out in early part of 1900's. But I had thought the phenomenon did not really display itself until 600 yard targets and beyond - perhaps it shows up closer as well?? - just a guess, on my part.

From working with No. 4, they are extremely sensitive to bedding - that is almost a "black art" by itself, to get the draws correct, the bearing for that one main action screw, the fit against the wrist, the various up pressure or no pressure against the barrel. The No. 1 and No. 4 were used for decades as medium and long range target rifles - so was also well investigated 60 and 80 years ago.

I had not previously thought of it, but I suspect that you may be interpreting "recoil" as a surrogate for velocity?? Not real sure if that is a valid assumption. I am not so sure about the blanket desire for "factory" ammunition, either - I think it varies - a lot. At least with the military stuff, it was fairly well defined - 174 grain bullets, 2440 fps - plus or minus 40 feet per second - so 2400 to 2480 fps. I believe that is what the original sights on the military rifle were set up for. I suspect it is a struggle to find any factory ammo that matches to those parameters??

Do not get caught up in the "silk purse - sow's ear" thing. The Lee Enfield No.1 and No. 4 were designed as battle rifles - to be "good enough" - so design was in the 3 to 4 MOA precision at 100 yards. Never were designed to be precise. Much work done at Bisley, etc. by civilian target shooters to "tweak" the bedding, etc. and I believe they achieved performance far exceeding original. Can see that in the Armourer Instructions issued by Canada Army - earlier versions described bedding procedures for standard military. About the last version also had a section about "tuning" that military bedding for competition shooting - so even Canada Army realized that improvements could be made - although the standard set-up was "good enough" for troops.

 

[jethunter]

So, I am finding interesting things with my smle sight settings to get point of aim and point of impact together.
The thing I think is happening in the amount of upflip caused by recoil greatly effects point of impact.

Factory federal 175gr; the site needs to be set to 450
Realoads with 175 over 38 grains imr4895 the sight needs to be set to 200 yards
I have also heard of 150gr shooting lower than 175, which contradicts what velocity would suggest.
My thought, the more recoil, the higher the point of impact, and this suggests a few things
Military ammo probably has more recoil than factory, either loaded hot or cordite is really fast.
I can probably get close to that with imr 4895 if I load hotter, but I don’t really want to push my hunting load, for better brass life.
I would like to get reloads that match the factory point of impact, so I am thinking a slower powder?
If I can find in I am thinking h4350?

I would like to scope it so if I can match factory loads with my main reload, that would be ideal.
I would also like to set up other types of reload with near same poi, but that may be a stretch.

Any advice would be appreciated.
Thank you.

I have a Husqvarna M46, 9.3x57, 26" bbl, 280gr bullet. The sights are fixed, can be drifted for windage but not for elevation, need to adjust the load to the sights. First load shooting low right about 5" at 100 yds. Increased load 1 gr - POI lower and righter. What the heck? Decreased load 2 gr - POI moved up and left. Continued decreasing in 1 gr steps - after several steps zeroed 2" high at 100 yds. First load 2050fps, final load 1850fps.

The recoil is affecting muzzle position before the bullet leaves the barrel. Light rifles, heavy bullets, long barrels, low velocity will all magnify this effect.

 

[Ganderite]

You can save yourself frustration and grief by starting with a search for ammo that groups well. Load a survey of powder charges in 0.5 gr increments and see what works.

Once you have a good load, just swap out the front sight for the correct height to put the bullets where you want.