compressed load

[pjeffreys]

ok guys i need some advice. i am working up a load for my 7mm rem. mag. and i'm using 139 gr sst bullets with retumbo powder. the manuals max load is compressed to the point that the bullet will not seat to my overall length. is this safe since the manual has not wornings by the load. i'm sorry but i don't have it in front of me so i can't tell you the exact weight. all advice is appreciated.

[stimpylu32]

The Lyman 49th says to avoid overly compressed loads as they can lead to jammed firearms , erratic ballistics , poor accuracy and other problems , thats their way of saying Don't .

The biggest problem is that an overly compressed load will continue to grow to the point that you may end up with a round that is jammed into the lands of the barrel and cause a seriously over-pressured cartridge .

stimpy

[GameHauler]

Interesting Lou
Are you saying that powder expands over time?
I do not have any compressed loads but just wondering.

[stimpylu32]

Ya Mike , With an overly compressed load the bullet will creap out of the case over time till it is no longer compressed , if you can lay your hands on a copy of the Lyman 49th , look on pg 63 .

Heres what it says , and I quote .

"Caution -- Avoid overly compressed powder charges , excessively compressed charges will cause the cartridge overall lengths to continue to increase after the loaded round is removed from the bullet seating die. This is caused by the elastic nature of the compressed charge trying to reduce compression by pushing the bullet upwards ."

stimpy

[Darrell Davis]

Hey there pjefferies,

You say you have "worked up" your loads.

Have you also checked velocities as you increased the powder amounts?

I guess I am wondering how you arrived at loads where the bullet cannot be seated to the correct depth without starting to see signs of a problem back a 1/2 grain of so before the problem load.

You could have a number of reasons for the problem, including the lot to lot differences of powder and/or brass.

If your brass is not the same as used by the testers writing the manual that could be a factor and even if it is the same brand, a different lot of the same brand can be heavy enough to cause trouble with case volume AND HIGH PRESSURES!

BE safe and keep em coming!

CDOC

[huntswithdogs]

First off let me say this, I don't like using compressed loads!

Of all the different cartridges, I've loaded since the mid 80's, some 308s are all I've had to compress. With the mag cartridges, I've had my best results with H4831. About the only things I've used Retumbo for was a 7mm and 300 Ultra mag. They need a lot of slow burning powder.

I used to look at the charts in my manuals, see which powder supposedly gave me the fastest velocities and started right there. I didn't take me long to get over all that. I wasted a lot of time and money trying to get fantastic accuracy at the highest velocity listed. Back your load down to starting weights and slowly increase it. Accuarcy, generally, comes together as the powder is increased and will reach a point where it'll start to open back up.


HWD

[helotaxi]

How you put the powder in the case can make a big difference on how much and whether you have to compress the charge.  I've seen a difference of as much as 3/16" in powder level in a .243 case with the same powder charge (I weigh every charge that I throw on the meter) just by slowly pouring the powder into the case while tapping the case with a fingernail or gently tapping the head of the case against my bench.  It allows the grains of powder to sort themselves out in the case reducing the space between the grains and squeezes more powder into the case without the need to use th bullet to compress the charge.

[Steve P]

I have been loading for a lot of years and I have very few loads that are compressed.  Of the ones that are compressed, none of them have powder exceeding total case capacity meaning the powder will cleanly stay within the case prior to bullet seating.

None, as in not even one of my reloads is based upon COL in someone elses book.  Every one of my COLs is based upon my firearm that I am loading for.  I hope you are also.

Now comes one of my little secrets that I learned years ago when developing long range shot shells.  If you charge several cases and place them in a reloading tray, you can get powder to settle deeper into the case without compressing it.  Just touch your reloading tray with a low speed vibrator.  I used a back massager and muffled it with my hand.

I was doing this with 7TCU loads where the powder came up into the neck.  When I would pick up the case to place into the reloader, I would periodically spill the powder.  I started charging 10-20 cases and touching the reloading tray with that vibrator.  The powder would swirl and settle a little deeper into the case.  Bullets seated much easier when I didn't have back pressure from compressing the powder.

Steve

[LaOtto222]

Steve - I am sure that works. I use a funnel to charge my cases and I pour it down the side of the funnel at about a 45 degree angle to the vertical. The powder sort of swirls around the inside of the funnel and then drops through the hole in to the case. I pour it slowly while doing this. This alone makes a difference of how high the powder is in the case. If I still have a problem, I have a 6" spout on a funnel that I use the same technique on. I rarely have a compressed load doing this, and if then it is very mildly compressed. Years ago I was trying to stuff a lot of slow burning powder into a small case. I actually split the bullet seating punch up the side (spitzer style). Thank goodness it was a RCBS competition die. RCBS replaced it with one question. Were you trying to seat bullets over compressed loads? Being honest I said yes, thinking this is going to cost me. No charge, they were just curious. I do not do that any more - no more compressed loads for me. Good Luck and Good Shooting

[Catfish]

I used to shoot alot of compressed loads in my old .270. With H-4831 and 110 gr. bullets you could not over load, and I loaded alot of them where I had to tap the cases to get all of the powder in the case. I never had any problems with any of them and they were tack drivers. I hear you can get into trouble compressing ball powder, especially in hot weather. It`s not that they will go over pressure as much as the powder will cake and not fire properly.

[Autorim]

You can always reseat the bullets. Some shooters seat bullets long initially then reseat just prior to firing. It can prevent cold soldering to the cartridge case.

[roper]

If you get a long drop tube and pour the powder slow 75gr of Retumbo will be below the neck and your bullet should just seat on top of the powder maybe be alittle compress but not enough to worry about the bullet backing out of the case.