Thread: Double grouping .... likely causes ?

A couple of pics - before and after fixing the mag box binding issue. Confirmed my diagnosis of the cause for double grouping.
This one before - a few different loads & pills all showing 2 shots in reasonable proximity (~1 moa) but the third flyer out by 2 -3in.


This one after (remember these are not proven loads in this set up, still very much starting load dev.) Chose two that looked promising even with binding max box issue and ran them again with max box fixed.

First group (at bottom) of 4 - the first shot is cold/clean bbl, next 3 show some promise just under 1 moa.
2nd grp, different pill/load looking better at ~ 0.75moa.

So now I can get on to the load dev. Beware of binding mag box !!! Kind a rookie mistake but hard to spot in this rifle.

Originally Posted by chainsaw

A couple of pics - before and after fixing the mag box binding issue. Confirmed my diagnosis of the cause for double grouping.
This one before - a few different loads & pills all showing 2 shots in reasonable proximity (~1 moa) but the third flyer out by 2 -3in.
Attachment 136045

This one after (remember these are not proven loads in this set up, still very much starting load dev.) Chose two that looked promising even with binding max box issue and ran them again with max box fixed.
Attachment 136046
First group (at bottom) of 4 - the first shot is cold/clean bbl, next 3 show some promise just under 1 moa.
2nd grp, different pill/load looking better at ~ 0.75moa.

So now I can get on to the load dev. Beware of binding mag box !!! Kind a rookie mistake but hard to spot in this rifle.

Hi Chainsaw,
It's good to see the pics.
Time will tell if you can now shoot consistent moa groups from now on. They need to be 5 shot groups. If so, you have solved the problem.
What I see in those photos is 3" groups in the top pic and 2" groups in the bottom pic. A single flier out of 3 shots does NOT make a second group. In a 3 shot group, two shots will usually be closer together than the other. Those photos don't show double groups, do they ?
This could just be a case of unsatisfactory grouping at first, which you have now fixed - well done !
I have trouble seating the mag box when I reassemble one of my rifles and its very easy to get wrong with proud sitting and rocking bottom metal. I found it very hard to figure it out. Not sure I have even now.

@mimms2 I am a complete noob at reloading-I've heard of ladder tests and think I have a grasp of the concept but for clarity could you please explain it properly?

Ladder test is great place to start in determining safe and max pressures for rifle/powder/ combo. But don’t tell you much if anything about accuracy. In my case above ladder tests done at start, but provided no clues about inherent accuracy or lack of. @csmiffy ladder test is a series of loads usually 0.5 gn powder more than previous one going up to book max, or slightly above if you take care and observe pressure signs carefully as you work up from lightest load. To be useful needs to be done with a chrony so you can measure speed for each load, and that will tell you quickly if the pill/powder is going to do what you want in your rifle

you look for tightest grouping out of loads tested,also where velocity flattens out....more powder wasted abov this point (what muzzle loading guys did with black powder by shooting over snow,when no black ended up on snow they knew all was being burnt in barrel)...if you lucky you will find load with low velocity spread close to top that gives good accuracy potential...then load in small powder differences either side of this,then change seating deepth slightly either way to fine tune it.....or you get load at sub inch and call it good and go shoot stuff and be happy you saved yourself from using another 25-50 loads to find something that wont do job any better....horses for courses.

cheers

or you chuck 41grns of said 2208 in case with primer up its bum and a round nose 180grn hornady in front and shoot stuff as its giving a moa grouping as it is and will be a sub 100,probably sub 50 yard load anyway......well thats what I did and so far cant complain with results LOL.

Originally Posted by Dev

Had my new rifle bedded by a “gun smith” then started hand loading for it, was double grouping and shooting like shit.. after chasing my tail for weeks turned out was the bedding job (last thing I checked I assumed it would have been done properly...) cleaned it up and was a new rifle.

Who was the smith that cocked it up?

holysmoke batman....my rifles dont even dream of 850 yards....and yip big fat round nose hornadies,lovely and soft and they dump energy fast inside animals....perfect for my kind of bush hunting.

so why take the piss out of someone who does load FOR THE TYPE OF HUNTING THEY DO????? in another thread on shooting groups on paper

Ive shot about 40 deer,all recovered and eaten...about same number of pigs,4 chammy and half dozen thar....more goats than care to remember and would be close to 5-600 wallabies...
rifle accuracy hasnt been an issue for me,how well I can shoot rifles has been at times.... 3 of those deer were taken at more than 300 yards and all 3 in the last few years since I sorted my shit out and actually grouped rifle properly so I was able to do so.....the last deer was neck shot at 60ish yards freestanding....and it was a fawn....with those loads mentioned above..... if it works why fuck around with it????not because some hotshot tells you your load is too slow thats for real......a wise man once said "many a great load has been ruined by a chronograph"
as true today as when it was said many many years ago.
but what would I know,Im just a grumpy old truck driving bush hobbit.

Cheers everyone-wont be done with a chrony and more likely old school. Couple of loads and if it works that's probably where it will stay.
The dud reloading my 243 has done a handful of stout loads and probably 20 run of the mill middling loads.
If the stout ones work and look ok and shoot better than the lower ones we might have a redo. Otherwise its like the old days with me growing up.
Buy a packet from the shop, sight it in and run with whats left.

dude reloading lol