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PostPosted: Sat Mar 17, 2007 11:02 pm 
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Benefactor
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Joined: Mon Apr 17, 2006 2:33 pm
Posts: 1217
Location: Lancaster, PA
Age: 45
Years ago I read an article. The subject was precision hand loading for accuracy.
This article appeared in a magazine devoted to hunters who typically shoot
at long distances. As might be guessed, the piece was all about the details
of building very special ammunition. The key to exceptionally accurate ammo
is keeping every factor, every component, as close to perfect as possible.

The title of this article was “The name of the game is the SAME”

In taking a ‘Look Inside’ the 7.62x54 Bulgarian light ball recently
available, I was thinking that another phrase might be more fitting.
“The name of the game is..... close enoughski”

In tearing down and examining various ammunitions I have come to expect
most to have some component, or some factor, less than perfect. With
few exceptions this has been true.

With this Bulgarian offering every single component and chosen measurement
factor had accuracy issues. No attempt is made here to be mean, and it must be
remembered that this is only 10 rounds, out of millions produced.

Let us take a look at the subject:

Image

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As usual, components were weighed with an RCBS 10-10 scale. Components were
measured with Mitutoyu digital micrometers and a Central caliper. The bullets were
pulled using an RCBS collet type puller mounted in an Ammomaster press.

The components found:

Image

The ammunition is brass cased, and berdan primed. Neither bullet nor primer is
sealed in any way. The bullets pulled with very little effort, but erratically. This was
due to the case mouths being crimped into bullet cannelures inconsistently. On
most loading equipment the case mouth crimp depth is dependant on case length.
The longer the case, the heavier the crimp, all other things being equal.

Image

The components were measured in as consistent a manner as possible, but some
measurements were made two or three times. It’s easy to move along quickly
when each measurement is the same, but when they vary so much extra care
must be taken to be accurate.

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While making neck diameter measurements, something special was noticed.
It seems the cases were sized quite small, then the bullets were seated in a
non-concentric way. In other words, they are not centered in the necks.
On seating, the bullets stretch the case neck. In this example the necks were stretched
all to one side, to the tune of .003” off center. This proved difficult to photograph,
but here’s my best attempts:

Image

Image

The neck diameters were also out of round by over .001”, but this was mostly caused
by the bullets varying at least that much in roundness.

Some data on case and cartridge dimension:

Over all length of loaded cartridges: From 3.000” to 3.020”, with a spread of .020”.
The optimal specification is 3.010 according to the Handloaders guide to cartridge
conversions.

Case lengths: 2.100” to 2.110” with a spread of .010”. Optimal is 2.050 based on
the same source. This case length variation accounts for the inconsistency of
case mouth to bullet crimp, in my opinion.

Cartridge base diameters stretched from .4821” to .4850”, with a spread of .0029”.
Case neck diameters varied from .3330” to .3358”, doing my best to deal with
the uneven neck stretch.

Once pulled down, the powder was checked and weighed. It’s a medium length
extruded grain resembling IMR 3031, but clearly not exactly the same.
Charge weights varied significantly, from 49.5 grains to 50.1 grains.
The powder appeared in decent condition despite its 50 year life
in an unsealed case.

Image

The bullets were interesting. They are a hollow base spitzer design. The indentation
in the base measured a whopping .160” deep. Bullet weight variations were on the heavy side
ranging from 150.5 grains to 151.9 grains, with a 1.4 grain spread.

The bullets have a lead core, with a copper plated mild steel jacket and a deep cannelure.

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Bullet diameters measured from .3092” to .3112” with a surprising range of .0020”.
That’s quite large by any standard I have ever seen. While these bullets should be safe
in any 7.62x54 rifle, accuracy of any kind would be amazing. Nominal bore
diameter in this round is .311”, with many hand loaders looking for .312” or even slightly
wider in the quest for accuracy. My own Mosin bores slug from .312” to .315”.
A bullet that much undersized must simply bounce down the bore.

There is a chance the very large indent in the base acts exactly like the one in the Minne
ball of civil war fame. Pressure pushes the bullet base walls outward against the bore,
sealing it and forcing it into the rifling. If this is the case, then accuracy might not
be horrendous after all.

Image

Also noted was the depth of bullet seating in the case neck. With variations, it averaged
a very short .217” deep. This is not even one bullet diameter. With rough
treatment the bullet will shift in the neck, once again damaging accuracy.
Treatment as ‘rough’ as chambering a round from the magazine might do this.

Image

Case weights were the widest ranging of any one lot I have ever seen. The lightest
was 145.6 grains, the heaviest at 152.5 grains, with a spread of 6.9 grains.
External measurements found no large difference, so I can only guess the
weight variation is due to case wall thickness.

A few graphs of the more interesting variations:

Image

Image

My conclusions are.... well..... just mine. To be honest I am no trained scientist
nor do I play one on television. I don’t have a big sweaty brain. Heck, I’ve never
owned a pocket protector in my life! I’m just an interested hobbyist attempting
to understand my interests a bit better, and share my interest at the same time.

I see nothing in this ammunition that screams *unsafe* to me. In fact, I suspect
it will be completely dependable. My only criticism is from an accuracy
viewpoint. I fully expect this Bulgarian 7.62x54 to be as reliable as fifty
year old military ammunition can be. It’s probably 100% sure fire, I’m guessing
it will function perfectly. That said, I am as curious as a hound in a sausage factory
to see how accurate this ammunition is. I also want to run it across my chronograph
which I have found to be a good indicator of accuracy potential, or lack of.

I’ll report back after that range day....... this should be interesting.
There’s always the chance my conclusions are completely wrong.
This might be the most accurate ammo ever fired in a Mosin Nagant.

Stranger things have happened. There was the time I ate all those
bean burrotos.............. I was wrong then too.

***********************************************************
UPDATE UPDATE UPDATE UPDATE UPDATE UPDATE UPDATE
***********************************************************

An OUTSIDE look, for a change.......,

.....at a few of the cartridges examined recently in the ‘Inside look’ episodes.

The weather today was gorgeous. All the nasty global warming has melted from the
range and even the mud is not too thick. Chores are done, Mamma is happy, and
the planets seem to be in proper alignment.

Range day!!

Image

Goals today were to validate some thoughts on various mil-surp ammunition.

The velocity measuring device I use is a Pact Model 1 chronograph.
While it’s a little long in the tooth (ancient that is), it’s been reliable
for years. Features are scant, but it serves nicely.

Image

The setup is nothing spectacular. One simple box of electronics that’s nothing
more than a glorified calculator. Two ‘sky screens’ are mounted on a bar at a preset
distance from each other, then connected to the magic box via cables.
The biggest task is getting the sky screens in position so the shooter doesn’t
blow them to pieces. That takes some small bit of fiddling.

Image

First up, and the most surprising candidate, is the Bulgarian 7.62x54mm light ball.
I have recently made this ammo a subject of a ‘Look Inside’ article on surplusrifleforum.com. ( viewto ... df32977dbf )
In that article I noted many, many issues that all pointed to probable accuracy
problems. The only way to verify the findings is to put bullet to paper, sending
them over a chronograph on the way downrange.

I chose my Tula ex-sniper 91/30 for this test, as it’s my most accurate Mosin rifle.
I shot two five round groups of the Polish light ball as benchmark. I noted average
velocity, highest velocity, lowest velocity, extreme spread, standard deviation,
and average deviation for each group fired. Numbers are as follows:
Average velocity: 2699 fps
High velocity: 2705 fps
Low velocity: 2682 fps
Extreme spread: 22.6 fps
Standard deviation: 9.5 fps
Average deviation: 6.7 fps

These numbers are really not bad, especially for military surplus ammunition
from a communist block nation. I would not be upset at seeing numbers
like this from my own hand loads. This probably contributes to the
accuracy of this ammunition from the Tula.

The groups were fired at 50 yards, paying heed to my older eyes and wish not to run
down to the 100 yard back stop every fifteen minutes.

The Polish light ball turned in a predictable 1.5” and 2” group at 50 yards.
Not stellar, but not horrible for a $90 rifle with surplus ammo. This rifle will
plant them all under an inch with handloads.

After checking velocity and accuracy with the Polish, next up was the questionable
Bulgarian light ball. What I found surprised me substantially. The velocity data:
Average velocity: 2756 fps
High velocity: 2773 fps
Low velocity: 2741 fps
Extreme spread: 31.3 fps
Standard deviation: 11.5 fps
Average deviation: 8.3 fps

Notice the numbers do not vary from the Polish light ball by any large amount.
Average velocity is slightly higher and spread is a bit higher, but not enough
to cause any concern.

The real shocker was when I checked the target, looking through my
new Barska spotting scope. To be honest, if I hadn’t just posted fresh clean
targets I would not have believed what I saw. The group was TIGHT. How tight?
It was tight enough that I tried again right away. The second group of five
printed to the same point of impact and the same group size. Velocities were
within a few FPS of the first group.

Image

The Bulgarian light ball easily shoots every bit as well as the Polish light ball, at
least in my Tula ex-sniper.

I don’t find that easy to say. Everything I saw when tearing down this ammo
and inspecting it told me it should not shoot accurately. Theories abound, and some
pop out at me. That said, they are only theories. When the rubber meets the road
this stuff shoots pretty darn good through my Tula.

Am I going to order some more? I hope to order a few more cans just as soon
as I have the money to do so. Against all odds this blasted stuff shoots pretty
darn good!

_________________
"Nothing is foolproof to a sufficiently talented fool".

[url]http://carteach0.blogspot.com/[/url]


Last edited by carteach0 on Thu Mar 29, 2007 6:17 am, edited 2 times in total.

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 Post subject:
PostPosted: Sun Mar 18, 2007 9:51 am 
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Mil-Surp Psychosis
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Joined: Mon Apr 17, 2006 10:25 pm
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Location: Stearns Co. MN
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Recent range testing I did confirmed your theory. A 91/30 that typically shoots ~2MOA fired 20 shot group of these greater than 8 1/2" paper width. Glad I only bought 1 300 rd can instead of stocking up. Measured a couple on my collimeter and results were off the chart. Also experienced minor case splitting BELOW the shoulder.

http://www.gunboards.com/forums/topic.a ... _ID=215502

That bullet is identical in design to the one loaded in 50's copper washed Hung. light ball, also tested in this session with positive results. Thanks for the info.

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PostPosted: Sun Mar 18, 2007 10:05 pm 
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Benefactor
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Joined: Sun Apr 16, 2006 3:58 pm
Posts: 901
Location: Birmingham, AL
Age: 53
Thank you for your time and efforts. I bought a can too. Haven't tried any yet. Interested to see how it shoots now. Was going to save it. Think I'll go ahead and shoot it.

TK

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PostPosted: Sun Mar 18, 2007 10:14 pm 
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Benefactor
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Joined: Mon Apr 17, 2006 2:33 pm
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Location: Lancaster, PA
Age: 45
I'm going to 'give it a shot' myself. If it shoots too poorly then
I'll try breaking it down for components. If it shoots at all
decently then it will be fine for practice.

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[url]http://carteach0.blogspot.com/[/url]


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PostPosted: Sun Mar 18, 2007 10:20 pm 
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Mil-Surp Psychosis
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Joined: Tue Apr 25, 2006 8:45 pm
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Location: Michigan`s Thumb
Age: 50
I opened my can of Bulgarian light ball, took my favorite 91/30 and went shooting today. To make a short story your theory proved to be right on the money. This ammo hits all over the target. I went through 40 rds and the best I could do was about a 4" 5 shot group. This was off sand bags at 100yds. This 91/30 will easily put everything inside 2" with ammo it likes. Other than accuracy I had no problems. No splits, and it runs through the action great. Like Polaris, I`m glad all I have is this one can.

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PostPosted: Sun Mar 18, 2007 10:39 pm 
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Mil-Surp Shooter
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Joined: Sun Apr 23, 2006 9:27 pm
Posts: 109
Location: Central Texas
Age: 38
Very good research ... thanks for taking the time to look at it!


PS. If you're not satisfied with it after field testing, send it my way and I'll shoot the rest of it for you :lol:


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PostPosted: Sun Mar 18, 2007 11:09 pm 
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Mil-Surp Museum Curator
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Could the result of poor standards be because of the metric system? I mean, .001 mm is too small to measure, and .01 is too big, right? Not sure, just throwing it out there.

Thanks for the ammo report Carteach, these have yet to get old! I'm actually finding myself looking forward to the next report each week. Great job. 8)

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PostPosted: Tue Mar 20, 2007 9:00 pm 
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Benefactor
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Joined: Mon Apr 17, 2006 2:33 pm
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Location: Lancaster, PA
Age: 45
Snake....

No, I doubt the problem is the use of the metric system.
Even in metric, measurements are close or not close.
I have metric Micrometers and they are just as easy to use.

Nope..... just not the greatest ammo in the world.
Then again, it's BATTLE ammo, not target ammo.

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[url]http://carteach0.blogspot.com/[/url]


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PostPosted: Wed Mar 21, 2007 1:22 am 
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Benefactor
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Location: Midlands of SC
Age: 37
Thanks, been waiting for this report. Confirmed my suspicions to stay away from this ammo while others are available. :)

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PostPosted: Mon Mar 26, 2007 2:11 pm 
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Joined: Sun Jun 11, 2006 1:14 pm
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Location: Oregon
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While I haven't shot any yet....

I have a tin of 300 or so and I have taken one round apart... and found a few things that differ from yours. But, nothing scientific.

First, my headstamp looks different than yours, with a simple 3 at 12o'clock and 53 at 6o'clock.
Assuming that is for March of 1953.

Next, my powder looked different than yours. Your little cylindrical powder is not what I've got. I have little flat squares, similar to the Yugo 8mm powder, but smaller in size. These little flat squares are maybe 1.5mm - 2mm long on each side.

Other than that... about the same. I took the bullet out with a vicegrips and the smallest bit of force.
I barely had to pull, just overcome the little bit of the casing that had a grip on the groove on the side of the bullet.

So, not sure if this means anything.... but mine has some differences from yours in components it would seem. Perhaps this means the Bulgarians totally reworked things in the winter of 1952, and began to produce seriously accurate ammo...

Or maybe they just used anything and everything lying about, including different types of powder.

Somehow I am leaning to the latter.

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PostPosted: Mon Mar 26, 2007 2:30 pm 
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Benefactor
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I understand the Bulgarians did change powder from 1953 to 1954. The only sample
I have has is 1954, bu I have seen a photo of 1953 powder and it is as you describe,
flake powder instead of extruded.

My guess is the ballistics will be nearly identical. The flake powder of that type
works nicely in cases of this capacity.

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[url]http://carteach0.blogspot.com/[/url]


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PostPosted: Tue Apr 10, 2007 10:33 pm 
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2 of you say you confirm his theory that it isn't accurate but the way I read it he is saying it is accurate.


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PostPosted: Wed Apr 11, 2007 6:01 am 
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Benefactor
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Location: Lancaster, PA
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Mosins tend to be picky about their ammo. Mine all prefer one over
another. Might be three 91/30's in a row, all shooting much better with one ammo, and
none liking the same one.

I can't explain why, but my one 91/30 does shoot this stuff good.

I bought a K to set aside.

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[url]http://carteach0.blogspot.com/[/url]


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PostPosted: Sat Sep 08, 2007 3:50 pm 
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FWIW, this ammo shoots relatively well in my Finn M-39. At 100 yards, I got groups somewhere around 3 MOA. I'll have to try it again at 50 yards, and with a better rest, for a closer comparison. I'll also take pictures.

Finn M-39s are supposed to have tighter bores than any Russian 91/30s, which may explain why it shoots well in my rifle despite the "loose" bullets. Or not. Clearly, the Tula ex-sniper used by the author is capable of performing at a similar level. I haven't slugged my M-39 so I don't really know the bore diameter yet, but a lot of 91/30s and M44s have a very loose bore. One M44 I owned briefly - and did slug - had a 0.315" bore.

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PostPosted: Sat Sep 08, 2007 9:44 pm 
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Benefactor
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Location: Lancaster, PA
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As an update: I have had the chance to shoot a fair amount of this ammunition, and have found a high percentage of the batch I have to leak gases past the primer.

Since I wear shooting glasses it does little more than pass a slight breeze past my face, but the gases are corrosive and mean I have to strip the bolt after shooting.

Accuracy is hit and miss, no pun intended (but not bad anyway!).
Some groups are pretty good, the next might have a few fliers spreading
it to six inches at 100 yards.

Regarding the reader with a different number on his head stamp, I believe that means it was made at a different factory. the 52/53/54 are dates, the 3/10 are factory codes.

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