Weight sorting 7.62x54r

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Hooda Thunkit

Hooda Thunkit

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Warning, this may be long.

I want to preface this by saying that I have been reloading for 30+ years. Mostly handgun, but over the years I've loaded rifle hunting and blasting rounds.

In the past few years I've gotten a bug for Military Bolt-gun match shooting at the local club. I'm not very good, I usually end up in the upper end of the middle of the pack.

I'm currently shooting a Finn M39, with home cast 185gr CWW, over 17gr 2400. I can shoot 2-3 MOA 10 shot groups, at 100 yds with iron sights. I'm shooting 280-290 out of 300 on scoring.

The problem is that I know my rifle can do much better. I get 6 rounds in an inch, then another 2 inches away. Then, everything goes to blazes, I'll get a 4" group. Then maybe I'll do 2".

I'm weight sorting the projectiles to within a grain. I clean the primer pockets, and neck size only. I check case length and trim as necessary ( usually only 2 or 3 out of 70 need trimmed) every 3rd firing. I've deburred the flash holes. I have not uniformed the primer pockets, they are deeper than spec even when new.
I'm using a Lee AutoDrum, which is very very accurate on drops.

So, I got a wild hair and weight sorted the 70 cases I used last weekend. These are all well-used PPU, I've got 10 firings at least on them.
147gr - 4
148gr - 6
149gr - 10
150gr - 20
151gr - 26
152gr - 4

I plan to use the matched weight cases in batches of 10, as the shot strings are 10 rounds each.

Here's the question, if you've made it this far -

Can I realistically expect any better consistency using the weight matched cases? From 147 to 152 grains weight, we're looking at what, 3% difference in weight ?

With the low pressure round I'm using, would it make a difference ?

I know, shoot it and see. I will do that at the next match, but is 3% case weight difference that much ?
 
Your cases are already reasonably consistent so I would not expect to see that much benefit, but it can't hurt. Have you tried loading jacketed bullets?
 
someguy2800 said:
Have you tried loading jacketed bullets?
Click to expand...
I haven't tried jacket, at least not in this rifle.

I'm really a low-buck shooter. The only reason I can afford to shoot the matches, is that I can reload inexpensively.
By using my own cast projectiles, I can shoot cheap. Adding another 20¢/Rd+ for jacketed is going to squeeze my fun budget.

I'm just not interested in shooting jacketed at the match.
 
I have indeed slugged the bore at .3105, I'm sizing the cast at .311. Next batch I'm going to size to .312, just to see if it makes a difference.
The Finn Mosins already have an excellent trigger, the one Smith makes is modelled after the Finn.


I'm using aluminum gas checks (told you I'm cheap), although I have used copper, and noticed no difference.

I'm annealing every 3rd firing - I've tried every firing, every 2nd, every 5th firing. 5 firings is too many, accuracy deteriorated. Every firing made no difference compared to every 3rd.

What is maddening, I can't seem to nail down a problem. It could very easily be my less than stellar technique, I'm not very experienced at this style of shooting.
 
Hooda, I don't believe you will see a very big difference with the weight sorted cases although I think you might see a small reduction in your group size. I am OCD pretty bad so this is the type of thing I always every possible variable in my reloading. However, recently I had an issue read some guys here help me figure out and it may make a difference for you as well. I always keep on my rifle brass separated by headstamp. I also way each case and measure each case and try to group a light brass together usually by weight provided there is an a large difference in case length.
What I did not consider was a number of firings on individual pieces of brass. For instance in a bag of Hornady brass I may have 10 that are once fired and 10 that are 3 times fired and 10 that have been fired seven times. Even with me annealing after every firing, the necks get thinner, resulting in less neck tension on cases that have been loaded many times. Get a big time boost in accuracy if all of the cases have been loaded the same number of times as well as having same headstamp. Anyway that's something else to try to maybe increase accuracy, made a big difference for me.
 
I highly doubt sorting cases to that level will make any difference. Sounds like you may have a shooting problem rather than an ammo problem, or perhaps both. I would try some other loads, including especially a jacketed load even though this is not what you want to hear. I've found the Hornady/Graf 174 SMK .311 to be especially accurate in my M39 over IMR 4064. I have also dabbled in cast loads, and got mediocre accuracy at best and discontinued the failed experiment.

Try a known quantity load, such as PRVI commercial FMJ or a handload with the Hornady/Graf or Sierra MK bullet in this caliber, and shoot a series of 4x5 shot groups and see if there is a pattern. You can never have too much brass.
 
It seems some cartridges are inherently more accurate. Have you considered going to the other side of the Baltic to Sweden?
 
Casefull said:
Huge waste of time. You’re dealing with crude Ammo. And even if it wasn’t crude ammo it would still be a waste of time. Sorry
Click to expand...
I don't understand this. Crude ammo ? Do you mean that the 7.62x54r is inherently inaccurate?
Or possibly that cast ammo is crude ?
Or that my handloading is crude ?

Perhaps you could expand just a bit?

Random 8 said:
Sounds like you may have a shooting problem rather than an ammo problem, or perhaps both.
Click to expand...

I'll admit, it could easily be me. I'm not the smoothest bench rest shooter. I've not had much practice at it compared to some of my competition.

Speedo66 said:
It seems some cartridges are inherently more accurate. Have you considered going to the other side of the Baltic to Sweden?
Click to expand...

Heh heh, yep. I've got an M96 Swede also. I've considered shooting that instead.
However, I've heard the Swede can be exceedingly persnickety when it comes to shooting cast in it.
 
I have weight sorted brass and have to say it is one of the least effective ways to shrink group sizes, especially if you factor in time spent vs improvement.

That said, if it didn’t require the extra manual labor, I’d do it.

I got this far in a machine to do it before I got sidetracked on other projects.



If it made mildly impressive reductions in group size, I would have already finished it.
 
Hooda Thunkit said:
I don't understand this. Crude ammo ? Do you mean that the 7.62x54r is inherently inaccurate?
Or possibly that cast ammo is crude ?
Or that my handloading is crude ?

Perhaps you could expand just a bit?
Click to expand...

I might be able to help. The first thought I had before I read the whole thread was to ditch that PPU brass. I have had bad luck with reloading it in 30-06 and 44 mag from a rifle. Further research revealed it is not a highly regarded brass for reloading.

My next thought was to get some Hornady or Norma brass to avoid all those brass problems.

Then my thought was to try jacketed bullets such as has been suggested by basically everyone who has responded to this thread.

All these suggestions have so far been answered with some form of “I like to shoot cheaply”

I understand you like to shoot inexpensively. I commend the effort and congratulate you on being able to still be able to shoot in these competitions.

In the worlds of cars going faster and group sizes shrinking, there reaches a point where scrounging and lapping at the bottom just won’t cut it anymore. You have a few options left but sorting your brass won’t become one until you start using better components and have a much more inherently accurate rifle to begin with. Like, something full custom as opposed to a milsurp of which precious few example are extraordinarily accurate.
 
earlthegoat2 said:
I might be able to help. The first thought I had before I read the whole thread was to ditch that PPU brass. I have had bad luck with reloading it in 30-06 and 44 mag from a rifle. Further research revealed it is not a highly regarded brass for reloading.
Click to expand...

Well, thank you for that. I did have my suspicion about the PPU brass when I measured the primer pockets of once fired, and it was already too deep.
I think I'll check in to obtaining some different brass.

earlthegoat2 said:
Like, something full custom as opposed to a milsurp of which precious few example are extraordinarily accurate
Click to expand...
I think you misunderstand the premise. It is a Military Bolt-gun match. All competitors use an issue bolt action rifle, with issue sights. The rifle needs to be in original configuration to compete.
 
Hooda Thunkit said:
I think you misunderstand the premise. It is a Military Bolt-gun match. All competitors use an issue bolt action rifle, with issue sights. The rifle needs to be in original configuration to compete.
Click to expand...

Well then, I suppose a Finn Mosin is one of the better tools for the job. Swedes and Schmidt-Rubins could come to play too. I don’t think my Jungle Carbine would stack up to well no matter what the ammo components.

I made that statement under the context of sorting your brass to squeak out a little more accuracy from your Mosin. Brass sorting begins to play a part in the most demanding of accuracy requirements of which a custom rifle is usually party to.

Good luck with the matches. :D
 
Weight sorting cases with that little variability in WEIGHT could actually be increasing your case variability in what matters - VOLUME.

Volume sorting your cases can improve your group size. Weight sorting typically will not. Guys have proven weight doesn’t directly correlate with volume, and have proven weight sorting doesn’t typically bring any improvement in consistency.

So my advice, either don’t sort the cases at all, or only sort by VOLUME.

Are you annealing your cases? Are the necks uniform? Are your bullets seating with consistent pressure (within 5psi)?
 
Varminterror said:
Are you annealing your cases? Are the necks uniform? Are your bullets seating with consistent pressure (within 5psi)?
Click to expand...

Annealing, yes. Every 3rd firing. Tried several increments, settled on every 3rd.
Necks uniformed - outside turned with K&M unit, cleaned them up.
Bullet seating pressure - no way to measure. They feel good when seating.

More than likely this problem is a combination of my relative lack of experience with this style of shooting, combined with questionable brass.
When my fun budget meets up with available, new brass, I'll rectify at least part of the problem.

The rest is just practice, I suppose.
 
Do the shots that open up your groups tend to string vertically?

I know this is outside the scope of your original question, but are you making sure that the bullets fired within a match are all from the same batch of alloy and casting session?

Are you heat treating and if so, when?

Are you crimping? How much, what kind of die do you use?
 
Bullets are indeed from the same casting session, one pot at a time. Straight clip on wheel weights, with a touch of tin.
Air cooled, weight sorted to within a grain: such as 185.00-185.99 grains is one group.
Crimped with a Lee rifle factory crimp die, really just a light roll.

The shots are not stringing vertically, more like 6 in a roundish inch, then one 2" away at 10 o'clock. Or, 4" away low off to one side or another.
No discernable pattern to the flyers. I've even considered it was lube purging, but even when I use a dip-lube (45/45/10 usually) it still happens.
 
Maybe borescope your rifle and check the crown. You could have lead build up.
 
You need to trim and clean cases before weighing them for it to mean anything, but if you do those two steps first weight is an accurate proxy for fired case capacity. During combustion, the brass expands and fills the whole chamber. As a result, with the exception of a little space in the primer pocket and around the extractor groove and head, everything should be "either brass or gas". Since the density of brass is consistent (especially with matched cases) the more brass weight there is the less space there is for gas.

Brass has a density of about 8x water and gunpowder of about 1x water. Changing case capacity and charge in tandem causes no velocity or pressure shift for very small changes. So as a rule of thumb every 0.8gr of brass weight difference is about the same at throwing your powder charges in a +- 0.1gr range. So for match loads where powder is weighed to +- 0.1gr, I'd want by brass to all be within 0.8gr or less, at which point the two would be contributing equal amounts of error to the overall charge. Achieving this level of consistency is one of many aspects of match quality ammunition.

Your case set with a 5gr range is the equivalent of throwing charges +-0.6gr or so. That's wide enough to move even a velocity node load off the node. For a non-node load it could cause wild variations.

I would say you are not loading match quality ammunition and should not expect match quality results with that case set.
 
^^^^^ Thank you.

That's the sort of info I'm needing.

So, until I obtain some better brass, I'm going to sort for weight again, in smaller increments.

I can have one weight for the group shooting (20 rounds), and another for score shooting (30 rounds).

There is my new plan.

I love having a plan.:)
 
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