I loaded up some copper clad Rainier bullets for a 9 mm Beretta and the test shots were all over the place. I seated them a little low for over all length when compared to a metal jacket cartridge. Does this effect accuracy if bullet is seated too low? Powder brands were unique and green dot and used accurate measure, but results were poor no matter what powder was used. OAL was low for all tests rounds.

Thanks,

Dan

Seating 9mm bullets a little low has less effect on accuracy but more on functionality. Seat your bullets to either reloading manual recommendations or same as a factory round for reliable feeding in semi-autos. Extreme cases of seating the bullets too low will greatly increase chamber pressure not to exclude feeding problems. Suggest you try a faster burning powder such as Alliant Bullseye, Winchester 231, Hodgdon Universal, etc. which flows through powder measures better. When shooting for groups, test fire all loads off the bench to eliminate human error. Adjust powder charges until the smallest group is obtained. I load in .3 gr. increments and will load no more than 15 rounds of a particular load. I mark each case with a felt tip so I know what load I am shooting. Tuning a load can be time consuming and frustrating but it all becomes worthwhile when you find that "pet" load.

Seating 9mm bullets a little low has less effect on accuracy but more on functionality. Seat your bullets to either reloading manual recommendations or same as a factory round for reliable feeding in semi-autos. Extreme cases of seating the bullets too low will greatly increase chamber pressure not to exclude feeding problems. Suggest you try a faster burning powder such as Alliant Bullseye, Winchester 231, Hodgdon Universal, etc. which flows through powder measures better. When shooting for groups, test fire all loads off the bench to eliminate human error. Adjust powder charges until the smallest group is obtained. I load in .3 gr. increments and will load no more than 15 rounds of a particular load. I mark each case with a felt tip so I know what load I am shooting. Tuning a load can be time consuming and frustrating but it all becomes worthwhile when you find that "pet" load.



Thanks for the feedback,

Dan

MOST handguns you wont notice it...some revolvers, you might if your a good shot. For the most part, follow the above advice and either follow your loading data OAL or use what the factory uses. Most autoloaders dont allow you much in the way of OAL tollerances and too long or too short will do nothing but cause reliabilty problems which can be a real headache!!

I always try to load auto pistol cartridges to the max overall length allowed by the magazine. This ensures the largest internal volume and therefore the lowest pressures per powder charge. I will shorten if feeding is a problem. The 9mm doesn't seem to be as sensitive as the 45 acp which is very particular about overall length to feed well. I have never noticed much if any difference in accuracy

Most 9mm data you see will have an OAL with it. The 9mm has a very small case capacity and the oal is an important part of the overall load for this round. If you seat a bullet too deep on a heavy charge you could run into pressure problems. You can get the correct OAL and loading data right from Raniers website...I'd go with that and see if your accuracy improves. What bullet weight are you shooting?

Unless you're trying to get maximum velocity, you'd probably be better off with some AA#2 or WW231 in my experience.

I've had good luck with Unique in the 9mm, but only with JHP's (Rainier are plated). Marshal Kane gives good advice re: faster powders, but your problem may be that Unique doesn't meter well in small charges. Top loads with Unique in the 9mm pretty much fill the case, so 0.1 grain plus or minus will make a fairly large difference in pressure. I prefer AA#5 with the 115 Rainier's, 6.5 grains with COL of 1.100" and a Winchester WSP. Note just over Accurates start load (7.0 is max) and a tad longer (they have COL of 1.095). Also, AA#5 meters beutifully from my Lyman. But note that it is even slower than Unique.