7.62X54R Powder Burn Rate

[hobit]

I'm about to start pulling bullets and powder from 7.62X54R Chinese surplus to load in .303 British. My question is in regards to the powder burn rate and / or what commercial powder does it approximate? Thanks gents.

 

[LUTNIT]

There's no way to answer that without some sort of chemical analysis. Every factory and every lot from the same factory could be loaded with a slightly different powder. They used whatever bulk powder they got, developed a load that produced the correct pressure and velocity (within tolerances) for that powder with the other components on hand, and produced the ammo. Cases from the same year from two different factories in the same country or even two different lots from the same factory could have a difference in powder charge of several grains because of this. Even if you weighed it there's no real way to tell what it is.

Modern commercial ammo is largely made the same way.

You may be able to get a close approximation with some testing. Fire some and chrony them. Pull some bullets and weigh the powder charges. Check published data and try to find a powder that will produce close to that velocity with close to that powder charge in 7.62x54R. That can tell you which powder it's somewhat close to. You could then try the close retail powder with the same loads and see if they chrony similar with the same components (use the pulled bullets and factory primed steel cases). If it produces a similar velocity, I'd say the surplus powder is somewhat close to whichever retail powder you found. You can then use data for that powder in the .303B with the appropriate bullet weight, maybe reduce it 10% or so as a starting point to work up from, and check velocity continually as you go just in case.

This is a more advanced technique and many will tell you not to experiment like this if you don't have quite a bit of experience.

Some people just take 80% to 90% charges from pulled 7.62x54R cases and load them as-is into .303B cases. Personally I'd want more data than that will really provide.

The issue is that 7.62x54R is a very variable cartridge when it comes to burn rate. It can run with anything from a medium powder like 4895 to a slower powder like 4350 or even 4831.

One common load swap is to take a 7.62x39 case, dump the entire powder charge into a .303B case, and seat the pulled bullet as well. These result in a reduced plinking load though; not a full power .303B load. This works because 7.62x39 has a much smaller range of burn rates that will work in it than 7.62x54R does. Nearly all powders in 7.62x39 will be somewhere near 4198 to maybe as slow as 4895 but not likely.

 

[H4831]

My advice is don't do it.
You would be going to all that work to save a very few dollars and you would, if you were careful, end up with inferior and unreliable ammunition for your 303.

 

[Suther]

My advice is don't do it.
You would be going to all that work to save a very few dollars and you would, if you were careful, end up with inferior and unreliable ammunition for your 303.

I'd check your math on the savings. Last time i did this i got 125 rounds of 303 for $45 ($40 for 125 rounds 7.62x54r, $5 for a box of primers).

And they were 100% reliable. Can't really comment on accuracy because I'm not a very good shot with iron sights, but printed a 3"widex8"tall group at 100 - which isn't bad for my lack of skills.

Do NOT use all the powder. I just used the dipper from my lee classic loader, which threw around 38.5 grains of the powder I was using. The 7.62x54r had about 44 grains in it. But you will need to experiment to see what works for you. And be careful!!!

 

[35Wailin]

Personally, I would not take an unknown powder from another cartridge and load it with a charge that will produce unknown pressure levels. That would be like playing russian roulette in my mind.

 

[bearhunter]

That powder should be fine if you follow appropriate loading procedures and do a couple of things. First, weigh each load you pull the bullets from add them all together and divide the total weight by the number of charges you dumped into the lot.

Check out the capacity of the 7.62x54 case as well as a 303Brit case you intend to hand load.

The pressures generated by the 7.62x54 can be different depending on what they were originally intended to be used in. I have had some of the surplus ammo that has different bullet weights. Heavier likely intended for machine guns.

I usually subtract the difference in capacities between the case volumes and make up the charge accordingly minus 5% for safety purposes. As long as you are using the pulled bullets all should be well.

Finding the capacity of each case is easy. Weigh the empty case then fill it with water and weigh it again. Be careful that you use a similar meniscus or the calculation will change.

Because your calculation works for this batch it may not work for another if the cartridge lots are different.

Err on the side of caution and all will be well. Hopefully you have enough ammo to pull apart that you can experiment with different loads.

Remember, be CAREFUL. Do not trust data from other people.

 

[leverboy]

Personally, I would not take an unknown powder from another cartridge and load it with a charge that will produce unknown pressure levels. That would be like playing russian roulette in my mind.

But. But he said it was Chinese ammo... har har

I have done the 7.62x39 transfer for plinking loads in the .303 but not tried the 54R... If you aren't comfortable working up a load with the unknown powder, you could still use the projectile and then a known powder that you have data for... It is the price/availability of projectiles for .303 that can be the biggest obstacle. I would use the powder, but start reduced and work up to a less than full house round that I didn't have to worry about. If you have a chrony you can slowly bring your velocity up to known pressures for that weight of bullet

 

[sail32]

The Lee reloading manual gives, " useful case capacity ", information.

From " Lee Precision Modern Reloading 2nd Edition New Format2004,by Lee Precision, Inc.

The useful case capacity for the 7.62x54r is 3.47 cc.

The useful case capacity for the .308 is 3.43 cc.

The useful case capacity for the .303 is 3.28 cc.

The useful case capacity for the .30-40 Krag is 3.49 cc.

The useful case capacity for the 7.5x55 Swiss is 3.90 cc, etc.

 

[CanAm]

What your asking is more a function of case capacity and bullet weight comparison than burn rate.

I do the same as your are planning and reduce the charge weight to well below the bottom of the bullet at seating depth, but above 50% case capacity. Then work it up to velocity from there.

 

[Ganderite]

Assuming the 7.62 ammo is 147gr bullets, weigh the powder charge. Say, for example it is 50 gr. Look in a loading manual and see what powder is shown for 147 gr, around 50gr. say it is 4350.

Then go to the 303 page and use the Start laod for the same powder with the bullet weight you use in 303.

If you have a Chrony, you can make sure you are in the right pressure range by checking velocity.

 

[hobit]

Thank you all for the tips and great advice. It's nice to know I'm on the right basic track that can now be tweaked with your input. The average pulled load is 44 grains, figure I'll start at 36 in the 303, based on some load comparison in the manuals. Bought a case from CanAm actually so will have some constancy in powder for testing and accuracy fun. On the price side of things I figure each round will cost me roughly $.30 per all in.

I was leery of the copper wash on the bullets and have found that after 15 minutes of tumbling with ss pins, the wash is gone as is most of the sealant which I figure will help with consistent seating; the bullets appear to have a thin copper jacket as they now appear identical in colour to factory ones. Any thoughts on this step?

Thanks again all.

 

[Ganderite]

Thank you all for the tips and great advice. It's nice to know I'm on the right basic track that can now be tweaked with your input. The average pulled load is 44 grains, figure I'll start at 36 in the 303, based on some load comparison in the manuals. Bought a case from CanAm actually so will have some constancy in powder for testing and accuracy fun. On the price side of things I figure each round will cost me roughly $.30 per all in.

I was leery of the copper wash on the bullets and have found that after 15 minutes of tumbling with ss pins, the wash is gone as is most of the sealant which I figure will help with consistent seating; the bullets appear to have a thin copper jacket as they now appear identical in colour to factory ones. Any thoughts on this step?

Thanks again all.

That sounds just fine. Load up from there in 0.5 increments to see what groups best in your rifle.

 

[kjohn]

Interesting thread. I have several nice old .303's that are constantly calling for action.

The idea of pulling the bullets from surplus 7.62x39 and using all the powder from them in .303 sounds like a plan.

I have a Baikal single shot in 7.62x39, so I can use the primed cases with some 700X and cast bullets. I say this because the single is easy to clean after blowing off corrosive primered ammo.

 

[fiddler]

I've been loading for several decades and I never load with unknown powder in any circumstances. Each to their own, but saving a handful of dollars and risk damage to myself or my classic milsurp rifles is not a chance I take when powder is not that expensive.

 

[Andy]

Thank you all for the tips and great advice. It's nice to know I'm on the right basic track that can now be tweaked with your input. The average pulled load is 44 grains, figure I'll start at 36 in the 303, based on some load comparison in the manuals. Bought a case from CanAm actually so will have some constancy in powder for testing and accuracy fun. On the price side of things I figure each round will cost me roughly $.30 per all in.

I was leery of the copper wash on the bullets and have found that after 15 minutes of tumbling with ss pins, the wash is gone as is most of the sealant which I figure will help with consistent seating; the bullets appear to have a thin copper jacket as they now appear identical in colour to factory ones. Any thoughts on this step?

Thanks again all.

The powder seems fairly fast, in the IMR8208-H4895 range, so with the same 147 gr bullets, 36.0 grs should be a reasonable place to start. As for me, I'd start at 34.0 grs and I'd also load up a few rounds with the same bullet and powder charge with IMR8208 or H4895, and compare MV's (using my chrony) with the IMR8208 or H4895 as the "control" powder. That's the way I always do it. It sounds like you don't own a chrony and probably don't have those other powders either- good luck, you'll probably be ok.

I've done this procedure several times with various pulled powders, and a few times I've used the powder in the 303 Brit (e.g. Czech 7.62X39 and 8X63 Swedish powder). I've done my testing in my P14 which is strong as bull, as a measure of safety.

 

[leverboy]

Interesting thread. I have several nice old .303's that are constantly calling for action.

The idea of pulling the bullets from surplus 7.62x39 and using all the powder from them in .303 sounds like a plan.

I have a Baikal single shot in 7.62x39, so I can use the primed cases with some 700X and cast bullets. I say this because the single is easy to clean after blowing off corrosive primered ammo.

I am also building up quite a collection of these primed surplus cases.... Loading WW boolits in them would be great, but can I expand, seat and crimp the steel cases as I would brass? Never tried loading them yet...

 

[bearhunter]

I am also building up quite a collection of these primed surplus cases.... Loading WW boolits in them would be great, but can I expand, seat and crimp the steel cases as I would brass? Never tried loading them yet...

The steel used in those cases is very malleable and forms quite easily. As I mentioned before, I am surprised that commercial manufacturers haven't switched over to them. Much cheaper than brass. Not as good for reloading but I have done several over a half dozen reloads each without any issues.