How do you reduce the charge in a load?

[njc110381]

Now I've got these 85grn bullets coming for the 6.5x55, I'm thinking I could load it down a bit to save noise and recoil, and maybe give better barrel life. Is it possible to slow the bullet down a bit more than stated as a minimum load? Maybe 2500fps or somewhere close?

 

I've read that this can cause pressure problems, so I thought I'd ask on here to see what you guys think. I'm using Varget.

 

More to the point, is it worth the bother? I'm only going to be shooting out to 150 yards max so don't need the full power potential. The ground is too flat for long range shooting. It's just a passing thought, if it doesn't work then it doesn't matter!

[Ronin]

Do NOT reduce loads below minimum stated powder weights in reloading manuals, you do run the risk of over pressure, with obvious potentialy fatal concequences.

 

My book states that the start load for an 85g bullet in the 6.5x55 with Varget is 41.5g = 3000 fps.

 

Using quickload as an guide I played with Varget powder charges untill I got close to 2500 fps.

 

I had to reduce the THEORETICAL load to 30.6 grains to achieve this, (which incidentaly makes only 1206ft/lbs with the 85g bullet so not deer legal)

 

However my point is that you are reducing the existing start load by 25% (1/4), you would potentially end up with uneven powder burn, over pressure and a dangerous situation.

 

IMHO it is not worth the bother

[njc110381]

That's weird! Mine says 40 grains start to get 3128fps. I guess it depends a little on the test gun maybe?

 

I understand the reduced load theory to a point. The powder never sits the same in the case and if there's not enough it can cause weird things to happen to the burn rate. I assume you'd have to use some kind of inert filler for it to work?

 

As you say, it could be dangerous. I'll give it a miss. I was just wondering if there was any kind of load using a small charge of fast powder, like in the subsonic .223 loads?

[Ronin]

My book is Sierra #5, all references are not the same, trust me

 

 

It can be done, Bruce Potts tried to make a subsonic 308 load several years ago for foxing I think - he ended up seating the bullets in reverse to get them to group consistantly.

 

IMHO, if you want a subsonic load - use a .22RF.

 

There is a way to get consistant ignition in reduced load cases by using a flame tube which carries the primer flash to the front of the case, but you cannot reload (deprime) the case without destroying the tube, there are a few smiths who have tried this in the states for large case / very slow powder applications, but have given up becuase of the aforementioned difficulties.

 

My advice would be use the powder charge combination that gives you best accuracy and live with it.

[njc110381]

Ok, thanks. I'm working with a lee book.

 

My gun seems to like light loads. My mentors ammo shoots quite badly through my gun. His chamber is slightly longer too, which I find odd. Mine seems to like the slower stuff. We loaded down the same heads and cases to start loads, and it groups ok. They're weird things rifles, I can see me taking some time to fully work them out

[silentsoulsleave308holes]

normally what you would want to do for top accuracy is to look in the manuals and see what powder gives the highest velocity with the lowest pressure, this means that you can run neer top speeds with minimal stress and pressure

 

to achieve what you want you MUST look for the lowest velocity with the highest pressure

 

you need to run between lowest xxxxx pressure and xxxxx highest pressure to be safe, so a powder that in the case of seeking near top speeds with min pressure for accuracy will no longer be safe when reduced down

 

you need to be in a particular safe working load for your rifle to be safe

 

other things to remember when seeking pressure are that bullets seated back in the case increase pressure, just as bullets seated in or near the lands

 

seating bullets out of case but away from the lands reduces pressure

 

the heavier the bullet and the slower it will can run

 

when looking in the full hodgdon manual, if I wanted to choose a powder for top performance for 95gr bullet in a 243 I would choose h1000 vel 3077 cup of 50,000. its only rival is 4831 vel 3052 cup 50,700, 4350 3087 cup 50,500 and 414 vel 3138 cup 50,700

 

so you can see that out of 4831 and 414, 414 gives the same pressure but gives more speed so you could drop the charge slightly to match 4831 and at the same time drop pressure

 

however h1000 gives almost the same vel for an even further rduced pressure so this would be my powder of choice for that weight of bullet

 

now in your case (no pun intended ) it would appear that your prssures need to be between 43,000 to 50,700 so looking down the list and bearing in mind your request I would say for 95 btbt h380 gives 2779 for 43,000, 4895 gives 2865 for 45,000 and varget gives 2870 for 45,000

 

now there would not be much to choose between 4895 and varget and if its ok to use a pressure of 43,000 cup as in the h380 then you may be able to reduce the pressures tested for the other two (varget or 4895) and the vel will proberbl go below the h380 when the pressures are matched so one of these would be the choice

 

that all said I cannot stress to you enough that loading down can be way more dangerous than loading over max so I would never recomend it

[Ronin]

Ok, thanks. I'm working with a lee book.

 

My gun seems to like light loads. My mentors ammo shoots quite badly through my gun. His chamber is slightly longer too, which I find odd. Mine seems to like the slower stuff. We loaded down the same heads and cases to start loads, and it groups ok. They're weird things rifles, I can see me taking some time to fully work them out

 

All rifles - even custom rifles when chambered the same will shoot differently....

 

With factory guns, if your mates has a slightly longer throat, I would suggest that a new throating reamer was used for his gun, they do wear out, especially when they only take a minute to chamber the rifle at the factory

[Vermincinerator]

njc,

A large air space in the case causes the powder to detonate (all go off at the same time) rather then combust (burn from one end to the other) even though all of this goes off in a fraction of a millisecond. a detonation will cause an explosion most likely resulting in a burst action.

 

Ian.

[Alycidon]

Vermincinerator is correct, the powder will detonate rather than burn. If you are lucky the rifle will be wrecked if not you may be wrecked as well.

 

The only subsonic that I am aware of is the .30 Whisperer, there are bits on it in Snipershide. Essentaily this is a .221 Fireball case necked up to a 30 cal bullet. Good for 100 yards, after than the trajectory is a pain, Bullets wont expand at that velocity and we will very prone to some very dangerous ricochets. Also almost certainly illegal energy wise.

 

Please leave well alone and stick to the book. 6.5x55 is fairly kind to barrells anyway I think.

 

A

[Guest northernchris]

I have some .223 cases that are of reduced capacity,they have been cnc turned from a brass alloy ,they only hold 9 or so grains of reloader 7.......................................that would be the way around it

[njc110381]

I have some .223 cases that are of reduced capacity,they have been cnc turned from a brass alloy ,they only hold 9 or so grains of reloader 7.......................................that would be the way around it

 

 

Fair play, you're keen! That's a really good idea, although maybe a little expensive.

 

I'd heard that the worn reamer was the reason for the throat variations. I guess that as long as the dimensions are within the tolerances there isn't a problem.

 

Thanks for telling me the reason for the powder detonating too. I knew it was a big issue but never knew how or why it actually happened

[silentsoulsleave308holes]

not sure how the idea came about that njc wanted to load sub sonic coz on reading his post I couldnt find it, only that he wanted to reduce the load a little to reduce recoil and noise????

 

funny how things go off topic,,,,,,a bit like chineese whispers

 

 

if working up a load from min to max you will normally find two accuracy nodes so you can pick the bottom one if that suits your needs