M48A Accuracy Issues

[Sentryduty]

Based on Patrick's numbers we are looking at a fixed drop rate of 0.22" per 100 fps change @ 100 yds, that really isn't a lot of elevation change versus velocity for sight regulation..

I think to best answer this question we would have to have a bit more specific information about the target and shooting conditions.

How big is the target "black" and where is your point of aim? Are you shooting with a 6 o'clock hold or otherwise? Or more accurately, how far below the point of aim (POA) is the point of impact (POI)?

I believe something could be a little out of sorts with this rifle's sights but it is important to establish the baseline before we work out solutions.

---------- Post added at 09:20 AM ---------- Previous post was at 09:10 AM ----------

Once again, a photo would save reams of speculation. But a photo of the front sight might well reveal that the blade has been seriously filed down, as a fix for the usual high POI of ex-military Mausers. This is commonly done to get the POI into the black with a backsight leaf setting that can be varied to suit different types of ammo.

If the front sight were filed too low would that not raise the point of impact? A tall front sight should adjust POI lower by sighting the muzzle lower than the POA, correct? Been awhile since I tinkered with iron sights.

[Calif-Steve]

Try to set the sights at 400 meters. That should bring you upon target.

[Patrick Chadwick]

if the front sight were filed too low would that not raise the point of impact?

Of course! I made the basic mistake of writing something in a hurry, when I should already have been somewhere else. If the foresight (as I guess) was corrected, it should have been made much TALLER, not shorter?

If that is not the case, then maybe the gun is a bent-barrelled lemon. I hope not.

The point remains valid: different types of ammo won't explain this one away. And a photo would clarify matters.

[Sentryduty]

No problem, I often transpose my up from down and right from left, when typing out a long explanation, and will admit that I drew a quick diagram to check myself before I mentioned.

The barrel could be the issue, possibly, I wonder if Mitchell's installed a tall front sight from a parts bins or somewhere that is too tall and simply needs to be regulated to the rifle?

---------- Post added at 11:46 AM ---------- Previous post was at 11:45 AM ----------

I think if we got a photo of the front sight block and a blade and block measurement, someone could compare it against a know good one for a quick check.

[Patrick Chadwick]

it shoots below the black and some shots shoot land below the target circle but still on paper.

It is important that we get some info about the grouping. If the grouping is really bad, maybe the bore is so worn that a lot of pressure is being lost in gas blow-by and the poor old bullet is just falling out of the muzzle*. If the grouping is good, either a high blade has been fitted - ot the barrel is bent.

Now what was it I wanted to say. Ah yes, I remember -

PHOTOS PHOTOS PHOTOS!

*No joke, I experienced that with my first efforts with the Hannover "Pickelgewehr". The Minie bullet failed to obturate and landed in the grass in front of the target. About 1.2 meter drop in 50! I could just as well have thrown it at the target.

[vintage hunter]

Originally Posted by vintage hunter


That's the cause of you troubles right there. PRVI/PPU 8mm is underpowered. Popular consensus seems to be it's loaded to SAAMI specs rather the European C.I.L specs. Muzzle velocities average around 300fps less than Milsurp or other European sporting ammo with comparable bullet weights. Give some S&B a try, it should solve your low POI problem.




Sorry, I don't think it will.

So one has to puzzle out why this one shoots so abnormally low, not waste money on all sorts of ammo.

If the grouping is good, either a high blade has been fitted - ot the barrel is bent.

Patrick, if you were to read the reviews on PRVI 8mm ammo you'd see the OP isn't the only one experiencing this low impact phenomenon. It's a common complaint that PRVI 8mm ammo is underpowered.

[mr.tickle]

I think to best answer this question we would have to have a bit more specific information about the target and shooting conditions.

How big is the target "black" and where is your point of aim? Are you shooting with a 6 o'clock hold or otherwise? Or more accurately, how far below the point of aim (POA) is the point of impact (POI)?

I believe something could be a little out of sorts with this rifle's sights but it is important to establish the baseline before we work out solutions.

The target used was an NRA 100 yd high power target.

NRA Official High Power Rifle Targets SR-1 100 Yard Slow Rapid Fire

Target as a whole is 21" x 21" the black is 6 3/8"

I was aiming at the center of the black. The shots were clustered in the bottom 3 inches of the target.

[vintage hunter]

I was aiming at the center of the black. The shots were clustered in the bottom 3 inches of the target.

The bottom 3 inches of the black or the target as a whole?

[mr.tickle]

The bottom 3 inches of the black or the target as a whole?

Target as a whole. I do not have access to the rifle at this moment as soon as I am able to I will post a pic. It was a collectors grade Mitchell's Mausers. So no one had it before me (at least between me and mitchell's)

[Sentryduty]

So like this?