.223 load development with IMR 4166

[ericbc7]

I recently did some load development with the new IMR 4166 and 75gr Amax (moly coated by me).
My Rifle is a .223 Tikka T3 Sporter with a 24" barrel in 1:8 twist. This is an ongoing project and I will update this post with details as I have time to do so. I loaded 4 rounds of each powder wt. and fired 1 round of each wt. to determine pressure concerns. I proceeded to fire 19, 3 round groups according to E. Cortina's OCW protocol.

First I post my chrono data and pics of primers.

The cases run from left to right and here is a close up of the higher pressure loads:

It seems i might have stopped testing before pressure was significant. I will load some more at higher pressure and see what happens.

following is my 3rd group of targets with target no. 4 corresponding to load #17

I did not see or experience any signs of high pressure and plan to extend this test to at least .6 grains above what i did here.
here is a pic of my set up:

does anyone have any insight on my process?

 

[243winxb]

Some primers show a lot of pressure or bushing the firing pin hole is needed or a magnum primer with a thicker cup. Most loads at Hodgdon max out at around 23 grs IMR 4166, running 53,000 PSI. I guess your ok till the primers fall out of the pockets. Good Luck.

 

[ericbc7]

I hear ya 243winxb. I bought 1k 205 primers (federal) a couple days ago that i plan to try with this new powder on a smaller scale in near future.

 

[fmetz]

Eric, could you please supply a link for your spreadsheet you are using for data entry as well as a link for your targets. Thanks,

fmetz

 

[mac86951]

All I can say is thanks for the Update. I'll have to get a pound and try it out.

-Mac

 

[jsthntn247]

You should hit another node around 25.5-25.8, I would go up and see if it could be reached with no pressure.

 

[afrench]

the standard non-mag, non-556 wolf small primer (copper color) is very, very soft. try it again with 205s or similar.

 

[ericbc7]

Just a reminder that I was shooting moly coated bullets and approach these loads with caution. I will try to post my targets and details soon. I am not sure why my es's are so big. All charges were dispensed with a chargemaster but will try fed 205s next.

 

[ericbc7]

Thanks for the insight jsthntn243, I will be expanding my testing with Fed 205 primers soon.

 

[jsthntn247]

Thanks for the insight jsthntn243, I will be expanding my testing with Fed 205 primers soon.

Your going to get high es with a chargemaster and small case capacity. Mine is only accurate to +- .1. .2gr difference in a case that small is huge.

 

[GrocMax]

+/- 0.1g at 26g at 2600 FPS will result in an 18FPS ES if we assume charge weight and velocity holds a linear relationship, all else being equal. Since it doesn't, there must be other factors involved. But its about the easiest one to measure, so we blame it.

 

[Brians356]

Most loads at Hodgdon max out at around 23 grs IMR 4166, running 53,000 PSI.

The 75-gr load on Hodgdon maxes out at 23.0 of 4166, but there are 7 higher max loads (up to 26.2) for lighter bullets.

 

[jsthntn247]

+/- 0.1g at 26g at 2600 FPS will result in an 18FPS ES if we assume charge weight and velocity holds a linear relationship, all else being equal. Since it doesn't, there must be other factors involved. But its about the easiest one to measure, so we blame it.

Most loads are going to have a 10-20fps ES any way. Add 18fps to that because of an over or under throw and you've doubled your ES. Not to mention the possibility of being out of the node when you are 38fps over or under your target velocity.