Interesting behaviour with my reloads

evgenk

evgenk

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Hey guys, I am observing weird behavior with my reloads. I'll start from beginning.

Reloading 7.62x54R with IMR 4895 powder, PPU brass, PPU 150gr FMJBT bullets and CCI Large Rifle primers.
One of my reloading manuals (can't recall which one) shows 42.5gr as a starting load and 48.5 for maximum.

I didn't have enough brass in January so I only loaded few rounds with 42.5gr of powder and recorded the best group of 1.05". When I finally got some more brass, I loaded a bunch of rounds in 1gr increments (5 rounds each) starting at 43.0gr and all the way to 49gr. Finally got a chance to shoot them all yesterday.

43gr gave me a 1.4" group, and it all went down hill from there - group sizes all the way up to 4 inches.
The barrel was fouled in with about 40 rounds before I shot the 1st group with 43gr of powder. Same with my first attempt which netted me a 1.05" group.

The cases from loads less than 46gr have soot all over them, but it's not too bad ... I guess the pressure isn't high enough to create a good seal.

Few questions based on this:

- is it really all that bad to have sooty cases? would the problem be lessened if I simply neck size my brass?
- has anyone ever seen their best group with a starting load?
- is it safe to drop down to 42gr (from starting 42.5)?
- I've heard this could be due to the short barrel length combined with a slow IMR 4895 powder. Would a faster powder help in this case?

by the way, shooting my Mosin Nagant sporter with a barrel cut down to 20", range is 100 yards.

Thanks in advance!
 
The only caliber that gave me the smallest groups at max loads was the .270win. I have found accurate loads at low or medium low velocities for every gun I own. My barrels thank me------15 loads plus from good quality brass. The prairie dogs , I believe , didn't care that my 220 swift or 22-250 was 250fps below max. They still did triple summersaults!! hehehe!
 
I've only been reloading about a year but I know my goal wasn't always to work up to max loads. If I got a load that worked near the beginning min load then that is what I stayed with. IMR has a fast burn rate I believe and not a slow burn rate. I use Hodgson 4895 a lot and love it. As far as your Mosin I've never had any experience with them.
 
Thanks guys! I'm not after the fastest loads either ... but having smallest groups with just the starting load is a bit weird. Only con ern is that there is not enough pressure to create a good seal.
 
I waited about 10 seconds between shots and about 5 minutes between each group. Took a 10 minute break before shooting last two groups and still with bad results. I guess i could try waiting a bit longer ... i figured it being -7 outside i dont nees to wait too long for the barrel to cool.
 
evgenk said:
- is it really all that bad to have sooty cases? would the problem be lessened if I simply neck size my brass?
- has anyone ever seen their best group with a starting load?
- is it safe to drop down to 42gr (from starting 42.5)?
- I've heard this could be due to the short barrel length combined with a slow IMR 4895 powder. Would a faster powder help in this case?
Click to expand...

-not bad, just dirty. Neck sizing probably wont help, annealing the case necks probably will.
-yes, all the time. Sometimes I do go a little below starting values.
-yes, both 4895's can be loaded as low as 60% of the maximum load for reduced recoil/youth loads. In this case that would be 29.1gr. There is an article from Hodgdon (owns the IMR line) outlining this.
-doubt it and most likely not. Unless your barrel is under 10" or so, your barrel isn't too short for the burn rate of most rifle powders.

I can pretty much guarantee you that 29.1gr of powder will produce enough pressure to properly seal the case. That is unless the cases are too hard. Annealing brass cases softens them; I anneal most cases every 3-5 firings. Some brands are too hard out of the box. I believe Prvi cases are pretty hard; good brass, but hard.

I've had my best groups below starting values once or twice. In I think all my rifles except my M96 Swede the most accurate load is within the first 1/3 of the load range, sometimes right at the start.

There are certain powders that can be dangerous if you reduce the starting charge. H110 is one often quoted for that but it's a magnum pistol powder used in 357 and 44 a lot, nothing like 7.62x54R. There are no rifle powders I know of in the suitable burn range for 7.62x54R that would be an issue.

There is something called a SEE or Secondary Explosive Effect where a light charge of powder somehow causes incredible pressure that can blow up the rifle. The cause isn't confirmed as far as I have read but there are several leading theories. One is that the primer causes a flash-over sort of effect on the powder which burns off the inhibitors that control the burn rate. After that the powder burns without the inhibitors which is much faster than any firearm is designed to handle. Almost all the accounts of this is unverified anecdotes but Norma did publish an article about it some years ago. They found the only place they could cause it to happen was with large capacity cases with around 1/3 volume charges of slow magnum rifle powders. 4895 is not a slow magnum powder and to get down to a 1/3 charge in a 7.62x54R case you'd be looking at under 20gr of most stick powders.

Anneal your cases (there are many methods, a quick Google search will turn up lots) and try again. If they still soot up after annealing them you may have a grossly oversized chamber or throat. I have this issue with a Martini-Enfield I have that has a massively worn out throat. No matter what I do I get at least a little soot on the cases, even new factory ammo does it.
 
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evgenk said:
Hey guys, I am observing weird behavior with my reloads. I'll start from beginning.
Click to expand...

Can you post decent quality pictures of your targets and some info about them?

* order they were fired in (so we can match the targets to the amount of powder)
* distance from the target
* scale on the target (give us a reference like 'this target circle is 5" wide)
 
Thanks! Btw, IMR 4895 load data and H4895 is not interchangeable. Completely different powders. The 60% rule only works with H4895.

Cheers!

LUTNIT said:
-yes, both 4895's can be loaded as low as 60% of the maximum load for reduced recoil/youth loads. In this case that would be 29.1gr. There is an article from Hodgdon (owns the IMR line) outlining this.

I can pretty much guarantee you that 29.1gr of powder will produce enough pressure to properly seal the case. That is unless the cases are too hard. Annealing brass cases softens them; I anneal most cases every 3-5 firings. Some brands are too hard out of the box. I believe Prvi cases are pretty hard; good brass, but hard.
Click to expand...
 
I'll take a few pictures when I get home.

HeavyTread said:
Can you post decent quality pictures of your targets and some info about them?

* order they were fired in (so we can match the targets to the amount of powder)
* distance from the target
* scale on the target (give us a reference like 'this target circle is 5" wide)
Click to expand...
 
You know the soot may what was left in your chamber from the previous round. As you pull the action back a small amount stays in the neck of your chamber and so on and so on - just a theory.

I have never shot PPU bullets. Maybe they are not the best a high velocities and the base is obturating (expanding) too much casing fouling. Buy some good bullets like Sierra, Hornady, etc and see if that tightens your groups back up consistently. I think you will be surprised.

Good luck
 
evgenk said:
I waited about 10 seconds between shots and about 5 minutes between each group. Took a 10 minute break before shooting last two groups and still with bad results. I guess i could try waiting a bit longer ... i figured it being -7 outside i dont nees to wait too long for the barrel to cool.
Click to expand...

No. does not sound like a heat issue with a 5 minute wait in cold weather.
 
Winchester-1897 said:
I've only been reloading about a year but I know my goal wasn't always to work up to max loads. If I got a load that worked near the beginning min load then that is what I stayed with. IMR has a fast burn rate I believe and not a slow burn rate. I use Hodgson 4895 a lot and love it. As far as your Mosin I've never had any experience with them.
Click to expand...

I drug out a burn rate chart and this is how they all shake out in the 4895 area:
- BLC(2)
- H335
- H4895
- Varget, IMR4895
- blank
- IMR4064, N-530
So the two 4895's have slightly different burn rates and likely can not be interchanged with data from one to the other but could probably both work given the right load.
 
Grey_Wolf said:
I drug out a burn rate chart and this is how they all shake out in the 4895 area:
- BLC(2)
- H335
- H4895
- Varget, IMR4895
- blank
- IMR4064, N-530
So the two 4895's have slightly different burn rates and likely can not be interchanged with data from one to the other but could probably both work given the right load.
Click to expand...

I use the H4895 exclusively in my Garand.
 
To answer one of your questions, 4895 is a very good powder choice. It is not a "slow" powder.

Groups must be statistically valid. Shooting one test does not mean much. The "good" group might be a fluke.

Clean the barrel with a good copper solvent. I wet it down and leave it over night, muzzle down on a paper towel pad. might need more than one over-night treatment to get clean.

At the range, fire a few shots to zero the scope, warm the barrel and foul it.

Then shoot the test, starting at 42 gr, in 0.5 gr increments. Make sure the barrel cools between groups.

If the gun tells you it prefers the mild load, don't argue with it.
 
LOL only if I could find better bullets in .311 diameter! None of the north american manufactures make these anymore as they're trying to fill back orders for the more popular calibers due to the hoarding epidemic that we have on our hands.

And PPU bullets aren't the greatest... the bearing surface is tiny compared to few other bullets I've looked at - but that's all I've got for now.

Muskyhunter1 said:
I have never shot PPU bullets. Maybe they are not the best a high velocities and the base is obturating (expanding) too much casing fouling. Buy some good bullets like Sierra, Hornady, etc and see if that tightens your groups back up consistently. I think you will be surprised.
Click to expand...
 
The 4895's are so close they're almost, but are not, the same thing. With a 180, their velocities are under 50 fps different. Data is still not interchangeable. However, if you can't find one, but can the other, you'll be really close. No going below minimum.
The 'H' starts at 46.0 for a 150. Hodgdon didn't test the IMR with a 150 when they did their on-line data, but my old Lyman book gives 43.0(your 42.5 will do, manuals change over time. It is 42.5 starting for a 180, according to Hodgdon.) to 48.0 for a 150. Velocities will be totally different due the the shorter barrel. Not a big deal. However, having the start load being the most accurate isn't entirely unusual. That may be due to the shorter barrel.
 
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