M48A Accuracy Issues

I have a M48A I had gotten from Mitchell's Mausers last year. The issue I have with it, is that it shoots extremely low. I use one of the NRA 100 yard targets and aim at the center of the target (with the sight adjustment slid all the way back). At 100 yds (the furthest I have been able to shoot it) it shoots below the black and some shots shoot land below the target circle but still on paper. I have done these shots from a leadsled. Is there anyway to adjust the elevation of the front sight? Is there something I am missing about these guns or did I get a lemon?

Also the only ammo I have used is PPU 8mm Mauser Match ammo. 200 grain FMJBT

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Originally Posted by mr.tickle

shoots extremely low

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Originally Posted by mr.tickle

the only ammo I have used is PPU 8mm Mauser

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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.

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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.

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Thank you. Is there any other brands besides S&B you would recommend? Is the milsurp yugo/PPU stuff you see often for sale is that CIL spec or SAAMI spec?

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Originally Posted by mr.tickle

Is there any other brands besides S&B you would recommend?

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Other than S&B all I've ever shot in my 8mm's was Turkish milsurp or my own handloads. I generally don't recommend items I have no hands in experience with but you might give the Hornady brand a go. Advertised muzzle velocities of 2500 fps suggest it's closer to European standards. It ain't cheap though, $33/20 rounds. About the only other option would be the Nosler offerings but it's ridiculously expensive at pert near $3 a round.

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Originally Posted by mr.tickle

Is the milsurp yugo/PPU stuff you see often for sale is that CIL spec or SAAMI spec?

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Just an educated guess but I'd say all/most actual military surplus would be loaded to European standards.
Do you reload? Might be your best option.

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Originally Posted by vintage hunter

Just an educated guess but I'd say all/most actual military surplus would be loaded to European standards.
Do you reload? Might be your best option.

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I just built a reloading bench and am working on getting all the equipment. Guess this gives me another excuse to hurry up and get everything set up! Do you know a good website that lists the CIL spec loadings?

Just shot the last of my PPU ammo saturday glad I held off on ordering more!

Thanks for all the help!

Milsurp Yugo is said to be good stuff. I have shot some of it in very limited quantities and never had an issue with it in both a K98 and an Egyptian Hakim. The Turk ammo is a little on the hot side compared to most other milsurps but that only really matters if you are shooting a Hakim. Stay away from the Syrian stuff.

I've also done extremely well with the Yugo M75. Both lots I have are from 1999 and shoot very well, even in my shot out gun. Be warned that even relatively new stuff like that is still corrosive and I think berdan primed, so not easily re-loadable. The old stuff is fine too but the M75 like what SGAmmo has right now is fantastic. I also agree the normal PPU is a bit under loaded though I've not shot the Match grade. Makes good brass for reloading though.

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Originally Posted by mr.tickle

Do you know a good website that lists the CIL spec loadings?

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Correction: the abbreviation for the Permanent International Commission for the Proof of Small Arms is actually C.I.P., not CIL as previously stated.
Hodgdon.com is good though it doesn't specifically list data C.I.P. spec data.
The 8x57 mauser round can be loaded to it's full potential using the data found in any reputable load manual. The working pressures of max loads are usually comparable to ammo of European origin.

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Originally Posted by mr.tickle

Is there something I am missing about these guns or did I get a lemon?

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Yes/maybe. Read on!

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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.

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Sorry, I don't think it will. IMHO, the whole thread about trying different types of commercial ammo is a confusing and expensive red herring.

Let's look at some simple ballistics, taken from the table in the Sierra manual for 175gn .323 dia. SPT bullets - and believe me, at 100 yards it hardly matters what type of bullet you use - and I use everything from round ball to 6mm BR boattails - it just isn't flying far enough for BC etc to make the kind of difference under discussion here.

Right at the top: 3200 fps. Drop at 100yds = 1.78"

Down at the bottom: 2100 fps. Drop at 100yds = 4.18"

So the diffence is a mind-boggling 2.4 inches! Which does not explain the following:

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Originally Posted by mr.tickle

At 100 yds (the furthest I have been able to shoot it) it shoots below the black and some shots shoot land below the target circle but still on paper.

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The number of Mausers I have shot must now be getting close to 3-figures. And up to now none of them shot too low. On the contrary, all were high to disastrously high. So with some of them I had to tack on a second bull below the target to get the shots to land in the black of the upper bull. The typical military Mauser was zeroed at 200-300 meters for a central hold, depending on the country. So one has to puzzle out why this one shoots so abnormally low, not waste money on all sorts of ammo.

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Originally Posted by Steve762

Easy fix! Slide the rear sight up to get the vertical shot placement you want.

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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.

So Steve's answer is correct. The sight was probably so drastically shortened because a previous user was shooting lead bullets, at a much lower velocity than any jacketed bullet. There is nothing wrong in that, as you adjust the backsight leaf to suit, but if it bothers you, get a replacement foresight blade.

Post a photo of the foresight, so we can all see if I'm talking tripe!

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 ----------

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Originally Posted by Patrick Chadwick

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.

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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.

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

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Originally Posted by sentryduty

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

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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.

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?

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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.

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Originally Posted by mr.tickle

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

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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.

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Originally Posted by Patrick Chadwick

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.

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Originally Posted by Patrick Chadwick

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

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Originally Posted by Patrick Chadwick

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

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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.

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Originally Posted by Sentryduty

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.

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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.

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Originally Posted by mr.tickle

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

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

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Originally Posted by vintage hunter

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

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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)

So like this?

Guys, I am not disputing that the PRVI ammo may be lighter loaded than other types. What I repeat is that it cannot be the sole explanation for such a serious drop as illustrated in the previous pic posted by Darren. If it's really that bad, the blade must be grotesquely tall or the rifle has a serious fault.

Who has the charts kicking around for sight radius and post height corrections and see if this is even in the realm of adjustment?

I just seen them the other day and cannot recall where.

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Ah here we go:

As an example, a K98 has a sight radius, rear sight to the back of the front sight, of 20 inches. 20/28 = .714. Multiply this by .004, .714 X .004 = .0028 inches. This is approximately how much you need to move the front sight to move the point of impact at 100 yards 1 inch.

Based on 7.5" vertical adjustment at 100 yards (3600"), with a sight radius of 20" Brownells calculator suggests shortening the front sight by 0.042" to correct the point of aim.

Next question to guys who actually own a K98 (Which I do not) is that a reasonable adjustment? Is there enough "blade" on that style of sight to do such a thing without filing it down to a useless nub.

More update, other Mauser forums tells of different height front sight blades, they suggest that the sight height is marked in (mm) on the underside of the blade when removed from the sight block. Common sizes seem to be 5.3mm to 6.1mm

https://www.milsurps.com/images/impo...ghtblade-1.jpg

0.042" is 1.0668mm so if we had a tall 6.1mm sight on the rifle a 6.1-1.0668mm = 5.032mm foresight height for a 100m zero.

I recall that we should be correcting to a 200m zero correct? (asking the audience) which should be about 2.5" high @ 100yrds (approx)? That would suggest that we would need even more front sight reduction, seems like we are on paper running out of foresight blade.

Can anyone check my homework?

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Originally Posted by Patrick Chadwick

What I repeat is that it cannot be the sole explanation for such a serious drop as illustrated in the previous pic posted by Darren

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Patrick, I've personally witnessed some of my friends shooting 196gr SP PRVI 8mm ammo on my range and seeing the bullets strike 4-6'' low at 100yds when fired from rifles(most scope sighted hunting rifles) zeroed to be dead on at that range with other brands of ammo loaded with 195-200gr bullets with an average muzzle velocity of 2550 fps.
However, if the OP's rifle is shooting as low as Darren's illustration suggests then I tend to agree with you on the problem being caused by something more than just sluggish ammo.

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Originally Posted by vintage hunter

If the OP's rifle is shooting as low as Darren's illustration suggests then I would agree that the problem is being caused more than just sluggish ammo.

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If I read the post correctly, and the "mockup" target I made is accurate, then I too am starting to think something unusual is going on with the rifle.

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Originally Posted by mr.tickle

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

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Originally Posted by Sentryduty

So like this?

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Yes that would be it!

Perhaps it would have been more accurate for me to say while my PPU ammo shoots low, it's low relative to surplus. At 100 yards it's typically 1-2" low whereas surplus is typically 1-2" high, depending on my skill level that day. So in thinking on it I agree with Patrick, something else is going on here, probably with the sights as mine also tends high despite some tweaks likely having been made to the sights back when the stock was cut for my grandfather to hunt deer with (it's since been debubba'd). The only ammo I've had shoot seriously poorly is 170gr Core-Lokt which shouldn't even be discussed in the same sentence as surplus or modern FMJ ammo for these. I had issues with wild groups due to stock fitment issues when I first got the replacement WWII stock for it but it wasn't shooting low.

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Originally Posted by mr.tickle

Yes that would be it!

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Good confirmation, thanks!

So gents, we have a rifle that is printing nearly 7.5" low from the expected POI, that should get us started.

Mr Tickle, can you post some photos of your front sight and possibly measure the height of the front blade to see what we are starting with?

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Originally Posted by Sentryduty

Good confirmation, thanks!

So gents, we have a rifle that is printing nearly 7.5" low from the expected POI, that should get us started.

Mr Tickle, can you post some photos of your front sight and possibly measure the height of the front blade to see what we are starting with?

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It won't be until friday or saturday before I can get a picture up. But I'll try to get one posted.

Does anyone know an easy way to remove the sight hood?

How To/DIY Mauser Edition EP.1 - Sight Hood Removal - YouTube

Or obtain a set of mojo sights.....love 'em

Sorry guys I've been traveling all week and have not been able to get a picture of the the sight. I went ahead and ordered some S&B 196gr fmj and some m76 yugo surplus just to see what difference it makes.

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Originally Posted by mr.tickle

I went ahead and ordered some S&B 196gr fmj and some m76 yugo surplus just to see what difference it makes.

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Be sure to post some target photos and a range report on the performance here. It will be interesting to see how the rifle responds.

Attachment 70294
Attachment 70295

I have the long awaited front sight pictures!

Excellent! Can you measure the height of the foresight blade at the tallest point to the flat of the base?

That looks to me like an extra-high (8-10mm?) blade, deliberately fitted to bring the POI down to a level where the backsight slider can be used for adjustment. There is probably nothing wrong with the rifle at all. Just do as Darren correctly suggested in his first post, and adjust the slider - that is what it is for!!!

Do not be tempted to file down the blade to "fit" the ammo you are using. That can lead to disaster when you try to use different ammo and discover that you have run out of adjustment range on the backsight slider! And if you nevertheless insist on filing it down, the blade will quickly become impractically wide at the top. If you then try to file the sides to reduce the width again, you need to be a master craftsman - or the blade will soon be FUBARed. Better to buy a slightly shorter blade, if you must. Best of all: leave the blade alone.

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Originally Posted by Patrick Chadwick

There is probably nothing wrong with the rifle at all. Just do as Darren correctly suggested in his first post, and adjust the slider - that is what it is for!!!

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I think Calif-Steve was the first to suggest increasing the rear sight setting, I must keep credit where it is due, but it appears to be a good fix given the situation.

Personally if it were my rifle I would try a group with ammunition you plan to keep using, and measure the vertical error, then measure the foresight that is in place, do the math and purchase the correct front sight blade.

I do agree with Patrick on filing the sight, one thing I did find with Mauser sights is that blocky pyramid shape isn't the most crisp to begin with, filing could easily make it worse.