Down right WIERD!

[grifter95]

I started reloading for my Romanian PSL saturday. I have had about 5 years of reloading experience with other calibers, but its my first try with the 7.62x54R.
Well I wanted to use IMR 4895 with .311 150gr Speer Spitzer SP. So I found the data in one of my books. It said 46gr (2425fps) start and 50.2gr(3120fps) max. So I started at 46.0gr and got 2437 fps. I then went to 47.2 gr and for 2612fps. Then I went to 48.2 and got 3160fps! I loaded another one to verify the power charge and got similar results. So I dropped it down to 48.0gr and got 2237fps? Whats up?
The only thing I can figure is that I'm not getting full burn from the powder. Maybe because its only filling up 70-80% of the case? I tested my chronograph with a known load and it checked out. I don't understand whats up here?
Any thoughts of advice on other loads to try?

[nalioth]

Maybe because its only filling up 70-80% of the case?
Isn't there something that can be stuffed into the case to take up space? Guncotton or something?

I don't reload, but I understand there is something like that available.

[bullseye]

Isn't there something that can be stuffed into the case to take up space? Guncotton or something?

I don't reload, but I understand there is something like that available.

you are referring to puff-lon www.pufflon.com
Are you using a magnum primer for this load? If so unburnt powder should not be an issue. How many shot that fast? Could it be slightly undersized bullets? Maybe you reached the pressure curve with your batch of powder and it is just faster that the lot used in the manual?

[Geilt]

I'll preface this by saying I am not familiar with anything special you need to do in regards to 762x54R so the following are basic questions.

First off you stated you've been reloading for years and this is the first time you've worked with 7.62x54R but it sounds like you're using a pretty standard set of components when loading up. Are you doing anything different from your normal reloading process?

Could be a number of things ranging a contaminated patch of powder (ie. small amounts of moisture causing uneven burn), iffy primers not throwing a hot enough or even ignition, an off lot of bullets from Speer or something as simple as a burr around the flash hole in some of the brass interfering with the passage of the primer's flame thus hitting the powder unevenly. Lots of possibilities.

Is this new brass or old? Could the cases be illformed and not mating with the chamber in some instances. Gas could be escaping around the mouth of the case and back instead of out through the barrel behind the bullet.

Do you need to crimp and this step is missing in your loads?

[grifter95]

Well the powder isn't bad in itself as I have used it flawlessly in my .308 fals and cetme. The brass is new from Grafs and I have inspected the primer hole and they all look fine. I started with normal WLR primers and switched to WLRM primers with no fix to the problems. Both boxes of primers have been used before without issue. The bullets are measuring consistantly what they should. And I have not changed my loading process.

Step 1) Size and prime
Step 2) Drop Powder (with electronic Lynman which I checked for accuracy) and add to case
Step 3) Seat bullet and measure to ensure uniform OAL
Step 4) Crimp with Lee Factory Crimp Die

It must have something to do with the combination? Today I worked up some more rounds using WIN 760 which takes up more case capacity. The maximum charge is actually compressed. It worked up consistantly without any suprises. I settled on a 95% load of 55.2gr under the Speer .311" 150gr Spitzer SP for a average velocity of 2767fps and ES of 15.21. This pretty much duplicates what I was getting from my surplus ball ammo and should properly "jive" with my scopes range adjustments.

So has anyone else tried the IMR 4895 with the 7.62x54R and had better results? I'm just doumbfounded and would like to understand the cause?

[Geilt]

Some combinations just don't work in certain firearms, hence the variety of available components. I have found that my Enfield loves CCI military primers and IMR powders but hates the same primers and Win 748.

[winky]

I havent reloaded for that particular round but ive got lots of experience loading. First thing i would look at is the primers of the fired rounds that hit 3160 compare them to one of the cases that had 2400 fps and see if they look more flattened. Then take a micrometer and mike the case heads of both just abouve the rim and see if one expanded substaintialy more then the other. Did you verifiy that 3160 load to see if it was repeatable? It is about impossible to drop .2 of a grian of powder and loose almost a 1000 fps. If I had to guess going by what you have posted id say you just got a funky chronograph reading. Sometimes if your to close to your chrono muzzleflash will efect it and as you step up in power your increasing muzzle flash and making it more likely to effect it. So if your chrono is close try getting it at least 10 feet out in front of your gun. If your using a cheap chrono like a chrony the sun and clouds can play havock with your readings and sometimes with the one i have i can just get an occasional reading that makes me shake my head. I use it at the range but when i get a wierd reading i take it home and check it on the ohler. You should absoulutely not need a filler with 4895 in the quantitys your using. It could be a bad primer thing but whats got me thinking otherwize is that your chrono is showing velocitys higher then the books says youd get with 50 using just 48 grains and that doesnt happen often. Alos if you truely got 3160 out of 48.2 and then dropped to 48 and got only 2237 that gun would have felt like a 22 going off when you lost a 1000 fps. So it brings me back to my best guess and thats your chronograph. What id do is if you do have your recovered brass and it isnt showing excessive pressure signs try repeating the whole test and shoot strings of 5 rounds of each load checking each case as you go for pressure signs.
I started reloading for my Romanian PSL saturday. I have had about 5 years of reloading experience with other calibers, but its my first try with the 7.62x54R.
Well I wanted to use IMR 4895 with .311 150gr Speer Spitzer SP. So I found the data in one of my books. It said 46gr (2425fps) start and 50.2gr(3120fps) max. So I started at 46.0gr and got 2437 fps. I then went to 47.2 gr and for 2612fps. Then I went to 48.2 and got 3160fps! I loaded another one to verify the power charge and got similar results. So I dropped it down to 48.0gr and got 2237fps? Whats up?
The only thing I can figure is that I'm not getting full burn from the powder. Maybe because its only filling up 70-80% of the case? I tested my chronograph with a known load and it checked out. I don't understand whats up here?
Any thoughts of advice on other loads to try?