I have always been told to maintain the same company cartridge when loading, not to mix say federal with RP etc. No one has given me an explanation as to why this practice is best. Recently I began weighing my cartridges prior to hand loading. I found each companies product to be of a slightly different weight from the others, Federal being the heaviest. I also found some variation, between 4 and 5 grams, within the same manufacture. I decided after some number crunching to throw out anything over 1 standard deviation with a manufacture brand.

Here are my questions. First, What are your experiences with deviations between companies on shells? On a 308 or 30-06 what has been the concensus as to the best firms product? Third, What are the thoughts of weighing shells, how much of a deviation from average is acceptable and will not impact the accuracy of the bullet?

Thanks for the help.

Brad

Here are my questions. First, What are your experiences with deviations between companies on shells? On a 308 or 30-06 what has been the concensus as to the best firms product? Third, What are the thoughts of weighing shells, how much of a deviation from average is acceptable and will not impact the accuracy of the bullet?

Brad

Most any American-made brass is of high quality, as is brass by many foreign manufacturers like Norma and Lapua. I'm pretty indifferent when it comes to brand, although I do tend to shy away from any nickeled cases as they seem to get brittle and split sooner than the plain brass ones after repeated resizing.

The weight of cases does vary from one manufacturer to another. Usually, this is a result of minor interior capacity differences. Of course, this means that an identical load will produce slightly different pressure (and velocity) in one company's case vs. another's.

As to how much deviation is acceptable, well, that depends upon your definition of acceptable. With most guns, I've found that using cases all from one manufacturer can, and does, make a measureable difference in group size -- but the difference in my guns is usually very minor. About a year ago, I loaded up a batch for my Model 29-2 .44 magnum, using both Federal and Star brass. I found that, on average, the benchrested groups using 3 of one and 3 of another measured .12" larger at 25 yards than the groups using only one brand of brass. For my use, this means to me that there is no real, practical advantage in sorting the brass for this gun, although the better accuracy results of sorting is undeniable.

Probably the best thing to do is to buy enough brass of your caliber from one manufacturer, and stick to that brand. That way you'll never have to fret the inconsistencies.

The weight variance is also that some cases are thicker than others and that will leave you shooting some rounds with higher pressure than others. Won't hurt anything, just might not hit what your aiming at. It is best to stay with the same brand.

I have not noticed any significant differences in my hunting rifles when using reloads of Federal, Remington or Winchester brass. Maybe if I was into benchrest shooting it could be significant. I do not weigh cases or loaded cartridges. All the best...
Gil

I have not noticed any significant differences in my hunting rifles when using reloads of Federal, Remington or Winchester brass. Maybe if I was into benchrest shooting it could be significant. I do not weigh cases or loaded cartridges. All the best...
Gil


Are some cases tha are drasticaly differnt in volume than other makes of cases...MOST of the US makers are close, but something like Norma .220Swift cases vs. R-P cases are farther apart. Far enough apaort to make a difference if a load worked up in one was used in antoher.

Some military cases are also different enough to make a difference (in genearal, miltiary cases ae thicker/less volume).

OTher than trying for the best possible accuracy or working with max. loads, seems that mixed cases get used most often. Certainly wouldn't do it when runnign close to the max. from a safety standpoint, but I seldom run any round past 3/4 throttle.

Once in a while it can make a big difference. My .35 Rem loads that work fine in Rem brass, won't even fit into Federal or Win brass.

Picked up a big bag of Federal .30-06 brass at a gun show once... on a whim, weighed them all. They were clearly from two different lots, and about a third of them had a LOT less case capacity than the majority. Could have made for some interesting surprises.

This question came up recently on another post. My answer then is the same as now.

Unless you're into some pretty serious benchrest shooting and chase ALL variables out to the "nth" degree, the variance in a grain or two of case weight doesn't really mean all that much. This is especially true if you don't load to absolute or beyond of case capacity.

Since most of my loads are developed for hunting, they don't top out the max load listed in the manuals. Have generally found the best accuracy is obtained just below the max listings, anyway. In these instances, you're not using all the case capacity, so a couple of extra grains in case weight don't matter.

Lots of other parameters will affect your accuracy more so, such as inconsistent primer seating, varying the bullet seating depth, the OAL of the case length and a few tenths of a grain of powder.

If you're not loading compressed charges, small case capasity variances are not going to affect much at all. In BPCR loading, everything hinges on powder volume and compression ratio which puts the case capasity at the forefront of concern for accuracy based on consistency. If you are not at a point where you're running a compressed load, small variations in case capasity are not going to affect you any.

Most of the affects seen from using cases coming from different lots and or mfg's is in the form of neck thickness, case length and flash hole uniformity. Thicker (heavier) cases usually have a thicker neck which will give you more pressure on firing which does change the parameters of the load, trim neck thickness to a uniform point for all cases. Flash hole size/shape variances can also change your load enough to be seen because the powder will not ignite at the same rate throwing the pressure/time curve off. Always trim all your cases to the same length, also because of pressure changes.

Lastly, use a big enough sample to provide sufficient data to compare. Most people are stuck on the three shot group deal but I don't buy into this. Put at least 10 on the paper and 20 or more is even better...then compare your groups for size, number of fliers, ect. 3, 4 or 5 shots are good enough to give you a fair idea if a particular load shows promise but what really matters is getting consistency round after round. If you can put 3 into .8" at 100 yds once and then put 30 more down range only to find your group has expanded to 12"....you have not done yourself any favors.

In many of my rifles, I load with different cases. Once they are all uniform, there is no appreciable changes in accuracy from to the other but I am not shooting 1000yd BR either. For my primary use as hunting loads, accuracy is fully acceptable and still well above and beyond what factory loads will do. In my '06 for example, I'm loading probably 8 or more different brands of brass including some mil-spec. I have uniformed all the cases and at 300yds, you can pull any specific rounds based on brass brand and get the same POI and group size as you will from any other brand.