When working up a load, most people say 5 shot groups, except in the case of belted mags, only shoot a 3 shot group. Why the difference in belted mags?

Umm, too goofy after three shots to hit anything else?

What's the need for more than 3 with an "Earsplittinloudenboomer!" If ya don't hit it the first time ya got the oomph as it's leavin and the 3rd fer that over the hill shot! By then it's in another state and you probably don't have an Out of State Liscense.

Seriously speaking though, a Belted Mag is usually what is known also as a "Overbore" with this kind of situation the barrel becomes heated very quickly due to the ammount of powder being used. They are also very prone to throat erosion that gets worse the hotter the barrel and the internal throat becomes very heated after 3 shots. This is the main reason for 3 shot groups with not just a Belted Mag but also a very good idea with any overbore round. A 220 Swift depending upon the bullet also the WSSMs, WSMs, SAUMs, Dakotas, Laseroni etc.

slimpickings111 wrote:

When working up a load, most people say 5 shot groups, except in the case of belted mags, only shoot a 3 shot group. Why the difference in belted mags?

Example:

I shoot a 416 Wby magnum.
Load consists of 120 grains of reloder 19. After 3 shots the barrel is steaming!!!!!

I think three is plenty with any round .. All five does is gives you a chance at two fliers ..
If you're looking at hunting accuracy ( moosis dont care if you're sub moa , moa or 2 moa if ya hit 'em hard and right ) , nothing to gain by five ..
Unless you're like me and just love to shoot ,, I can easily go out and free 100 cases of their bullets and powder , just so's I can refill 'em again ..
Jack

Welcome to the HuntingNut slimpickings111. I start off shooting 3 round groups when I'm working up a load and when I start to hit on one I shoot 5 shot groups while fine tuning it, in a standard or magnum caliber, letting the barrel cool between shots. Those mags do heat up the barrel fast though

Joe

I agree with Jack (sorry Mr. Moderator). I have always fired only three rounds in a group for a rifle. I do use 5 for handgun though...

Bushmaster wrote:

I agree with Jack (sorry Mr. Moderator). I have always fired only three rounds in a group for a rifle. I do use 5 for handgun though...

Nothing to be sorry about Mr. Bushmaster I just prefer 5 (It keeps me at the range longer )
Joe

Not really...If you shoot 5 and wait for the brrel to cool down it takes less time then shooting 3 and waiting for the barrel to cool. With 3 you have more waiting times between strings... Besides I take anywhere from two rifles and 5 or 6 handguns, a large sack lunch, plenty of water. and a whole bunch of bullets. I'm there from can see to can't see. My friend that owns the ranch that the range is on is thinking of charging me by the hour instead of by the day...

I let the barrel cool between each shot so I'm shooting from a cold barrel each time.
Joe

Looks like we both will be there all day...

Couple of comments/observations:

What I want to know with my handloads is how the rounds will group from a cold clean barrel. I know many hunters that foul the barrel before going afield, yet, in several of my rifles the first round from a cold and clean barrel will be no different than subsequent shots.

Too often riflemen evaluate loads @ 100yds and assume that 200, 300 etc will give the same MOA. IMO it is important to group @ 200yds as bullets will often either stabilize or destablize between 100 and 200. If the goal is to find a statistically repeatedable accurate load, 7 to 10 shot groups (again, at 200yds) will give more valid results.

An instrument critical in the development of loads is the chronograph. Actual readings of velocity will often differ significantly from interprolated published data. Loads with low SDs will often be the most consistent in accuracy as well and this, too, will show up more @ 200yds than shorter distances.

That said, load development begins with defining what range and what game is being considered. After defining that, then velocity and maximum appropriate groups size can be established with the chosen bullet(s). With the aid of today's manuals and programs, it shouldn't take very many experimental rounds to identify a load that achieves all these goals. In fact, most of my handloads have dialed in with less than 40 rounds fired.

I agree, initially you need to shoot your groups at 100 yards and then you need to do the same at all ranges out to your personal maximum.

On top of this I also chrono my loads at 100 yards once I get sighted in and feel comfortable in placing my chrono. You would be suprised at what you can learn about your loads when you do this. It has given me a lot of insight and also a lot more confidence knowing the actual loss with my handloads. I have also used the chrono at 200 yards but that gives me the willies at times. It has to be a very still day to do this.

Yeah 100 yds with a chrony is not so bad , but two hundred ?? Had a friend plug his unit on the first shot at 200 , he were hot ..
Handloader you'd be surprised at how many I know ( you may know 'em too ) , who never used a chronograph , and look at the load data in a manual , and say well 70 grains with this bullet is good for 2700 fps , and go look at a drop table for that combo , then wonder why they dont match up ..
And most will call yur chrony a liar when they fire a couple over it ..
Hah yeah if MOA worked that way would be nice , eh ??
Jack

When I'm working up loads, I usually start at 50 yards. My reasoning is that I'm looking for the load's accuracy and I want to eliminate all other factors, mostly human error. Once I have some good loads, then I move it out to 100 yards and beyond if the cartridge and hunting range calls for it.
Don