very similar cartridges

Elvis · Posted: Tue Oct 10, 2017 1:27 am Post subject: very similar cartridges

ok you reloading gurus here is my delema and solution.... Scratch

did I get my maths right??????

mates rifle uses a .204ruger case necked back up to .224 cal
so its parent the .222 magnum has shoulder about 2mm --1/16th" shorter and little bit less powder capacity

we did bit of a ladder test using win 748 powder and 52grn projectiles and topped out with pressure at 30grns
29grns was fine so we loaded and fired a few of those all ok

so looking in older manual that has .222magnum data
it appears to be this cartridge/rifle runs about 1.5 grns more than the 222 magnum

looking at data for the .222magnum it drops a full grain of powder per 5grns projectile weight

SO if I use .222 magnum data and add 1 grn to that I should be about right???????
have loaded up 20x 50 grn loads with 29grns powder so have kept load same but dropped 2 grns projectile weight
also 4x 70 grn loads at 27 grns....the data for 222mag had 26.5grns

Scratch

am I doing maths right???????

plurry lot of pissing around compared to good old .223 Sad

look forward to your replies

slimjim · Posted: Tue Oct 10, 2017 5:59 am Post subject: Re: very similar cartridges

Ok, Elvis. 5 grins of bullet is 1.0 less grain of powder. Going from 50gr to 70gr pill would be a reduction of 4.0 grains. 29-4=25 30-4=26 26.5 is higher than either. You might load one or two 70 grain bullet with less powder and test fire them first, e.g., 25.5 and 26.0. If 26.0 is ok pressure wise then proceed. Also, mark the impacts as these first three shots might give a clue to the accuracy node depending how they group.

Elvis · Posted: Tue Oct 10, 2017 11:38 pm Post subject: Re: very similar cartridges

ok from manual .222magnum data
40grn =26.5-29grns of 748
50grn=23-28grns of 748
60grn=22-27grns of748
70grn=23.5-25.5grns of 748

so it looked to me like Embarassed

I COCKED UP ABOVE POST Embarassed

good spoting Slimjim

its 1 grn less powder per 10 grns projectile weight

we tested a 52grn and settled at 29grns
so my 50grn projectile loads with 29grns powder will be fine.

agreed the 70 grn loads are 1.5grns above magnum data....which is not the 1 grn predicted.
will try em and see,they are barnes tsx with huge grooves around then to ease pressure..... dont have many of them but just had to try them out in the 1 in 8" twist barrel......
funny part is my mate thought he was stoking far more powder in than what we are now......

slimjim · Posted: Wed Oct 11, 2017 5:19 am Post subject: Re: very similar cartridges

Elvis, since its not your rifle, you might still load two more at the 0.5 grain less powder increments just to be safe. If the Barnes bullets are more than 0.050" from the lands, you are likely ok but .....

Elvis · Posted: Wed Oct 11, 2017 11:42 am Post subject: Re: very similar cartridges

cheers Slim.

Elvis · Posted: Sun Oct 15, 2017 12:41 am Post subject: Re: very similar cartridges

well that was exercise in frustration.... first shot 4" high then two 1" apart..all 2" to left.
fired single 70grn load and it pierced the primer.....thats a first for me ever.absolutely no flattening of primer just neatly pierced. will pull loads and put the powder to better use in .223.
oh and the 70 grn was 3" to left
lad lost all confidence in rifle after first shot went that high,along with the 3 misfires we had the other day.looked a bit harder at rifle and cant see bedding anywhere,that along with the chopped magazine box to fit extra length make it a hackjob....Nathan far happier to use the .308 BLR......fair enough.

slimjim · Posted: Sun Oct 15, 2017 4:54 am Post subject: Re: very similar cartridges

Elvis, thanks for reporting back with the results. Was the first shot that went high from a clean bore? I typically see that happen and make sure I put 1 or 2 rounds down the tube before I do any shots for accuracy.

Elvis · Posted: Mon Oct 16, 2017 1:04 am Post subject: Re: very similar cartridges

well sort of.....lightly oiled rag on jag been pushed through it before storage but not copper solved etc.
all my other rifles get same treatment and all shoot cold bore to same place as the rest.

slimjim · Posted: Mon Oct 16, 2017 5:44 am Post subject: Re: very similar cartridges

Elvis, this rifle may be different. Once hunting season starts, I don't clean my rifles or touch the bore until the season is over. If I have to clean/touch the bore, I always do at least 1 fouling shot. I've seen 3" of POI difference between cleaned and fouled. Once a sniper goes into the field, they don't touch their bore either.

Vince · Posted: Mon Oct 16, 2017 12:34 pm Post subject: Re: very similar cartridges

When I was in the Army whenever we went to the range , the order was always two fouling shots before doing any shooting. However, we religiously cleaned our rifle thoroughly (only with CLP) at least once a day, leaving the bore oiled...especially in wet weather. I guess they figured that when the ‘heat was on’ the average grunt would be firing more than a couple of shots and didn’t need pin point accuracy, just a hit, so fouling shots weren’t an issue.

Elvis · Posted: Tue Oct 17, 2017 1:37 am Post subject: Re: very similar cartridges

ah the good old CLP...love the stuff...always thought they should make TV add with Queen as sound track.....I've got my "break free"......