N130 or N133 .223 loads

[IanB 0]

Currently using N130 for my .223 loads, but I see a lot more are using N133 over this, any reason why the N133 seems more popular.

[dicehorn 38]

Hello Ian

Good question!  N130 burn rate is .7350 whilst N133 is very much slower at .4279

I have used on several standard twist barrels (I in 12) N133 using exclusively the 50 gr Vmax with generally pretty good results. Seems that with N133 the case needs to be pretty full just under compressed load values to get decent muzzle velocities, the upside being the powder/bullet combo provides consistently accurate rounds.

Last year aware that using the slower N133 maybe have its limitations I looked at both N130 and N120 as they both have very similar burn rates with the N120 a tad quicker. The next 223 that came to me became the guinea pig for N120, must say I was not disappointed. Hopefully I have attached two copies of targets for both N133 and N120

In my opinion the two powders + your N130 are perfectly acceptable powders for this little calibre. By contrast when I developed a load for a guy from N Ireland in his custom 1 in 8 twist 223 I used N140 with the 77gr Lapua bullets - will try and get a copy of target up which was before I spent time on the chronograph

 

 

[IanB 0]

Some cracking groups there dicehorn, what magnification scope are you using for load development. Also do you prefer to develop a load working up charge weights with group sizes or do you look for the least FPS spread then tweak COL to reduce group size. 

[dicehorn 38]

Hello Ian

Thanks for the compliment.

Those targets were with rifles bought to me so I cannot remember what magnification I used - I would guess as low as possible. When I shoot with my Tac which has an NXS on, I will shoot at 1/2"  targets using no more than X6. Reason being, aiming at a very small target sharpens your concentration. I also shoot with both eyes open!!

Regarding load development , I am a disciple of the OCW method with a final tweak on COL. I do have a Magnospeed V3 to chronograph results but must confess use it mainly to provide drop charts. Some of the better benchrest people have amazing groups at 600 yds but still have ES nearly at 20 and SD in double figures. My Tac on 10 shots gave an ES of 7 and an SD of 3 ..............once! 

Regarding OCW test method,  I copy a photo of an OCW target I shot about 4 years ago when I was finding it hard to source my usual 39gr SBK bullets so decided  to test 40gr Vmax in case I totally ran out of the 39's, luckily the 39's famine ended so the Vmax recipe sits in my folder.

 

[IanB 0]

Great groups again, 6x mag!!!! I wouldn't be able to see a 1/2" target and get accurate groups at that range, 16x minimum for me 24x preferably .. How far the .223 40gr off the lands?

[dicehorn 38]

1 hour ago, IanB said:

How far the .223 40gr off the lands?

Ian if you are referring to the OCW target above - the rifle was (as stated in middle of target) a 20 Tac and the bullet was seated 223 thou back from the lands.

On 24 x mag I think I would wander around the bull too much!!