.243 Win 105 amax - starting charge weight

[Rmitch223]

I'm about to begin load development with my Remington 700 SPS Varmint in .243.

I will be loading the 105gr Hornady Amax with IMR-4350

My questions is this. My Lyman manual shows a starting charge weight of 35.2. Hodgdon's load data shows a starting charge weight of 36.7

Before I saw Hodgdon's data I was going to start at 36gr and work up to 39gr in .5 grain increments.

Is it safe to start with 36gr even tho that's below Hodgdon's starting load charge weight?
Once again it is higher than Lyman's starting load at 35.2gr


Thanks,

Ryan

 

[DrMike]

The differences in charge weights can be accounted for by lot-to-lot variations, differences in cases used and differences in primers. Hodgdon specifies WLR primers and WW cases. Lyman only specifies LR primers and Remington cases. Given the differences in maximum charges, either lists starting charge weights of approximate 90% of maximum. You should be perfectly safe to begin your load development at 36.0 grains of IMR4350 and work up in safe increments. The difference in maximum charges between the two manufacturers is 1.0 grains. When you reach 39.2 grains, as listed in the Lyman 49th Manual, examine your cases to see if there are pressure signs. If velocities are within the expected parameters (2749 fps in a 24 inch barrel), you can, if needed, test to 40.2 grains as listed by Hodgdon (again, examining cases for signs of excessive pressure and watch velocities to see that they are with stated parameters (2870 fps in a 24 inch barrel)).

 

[FOTIS]

You'll be fine

 

[Rmitch223]

Thanks for the advice guys, I appreciate it.

I'm gonna start with 37gr and work up to 39gr in .5 increments and if need by next time around I'll start at 39.5 and work up to 41 or 41.5.

I'm gonna load 10 rounds of each and shoot a 5 shot group at 100yrds and a 5 shot group at 200 yards.

 

[Woodycreek]

The 105 Amaxs shoot great in my 700 SPS-V using Retumbo, Win brass, and Fed 210M primers. Good luck!

 

[FOTIS]

Cartridge : .243 Win.
Bullet : .243, 105, Hornady A-MAX 24562
Useable Case Capaci: 47.936 grain H2O = 3.112 cm³
Cartridge O.A.L. L6: 2.710 inch = 68.83 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : IMR 4350

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-10.0 83 36.45 2601 1578 40981 9156 96.2 1.410
-09.0 84 36.86 2628 1610 42200 9255 96.6 1.391
-08.0 85 37.26 2654 1642 43453 9350 96.9 1.372
-07.0 86 37.67 2680 1674 44742 9443 97.3 1.354
-06.0 87 38.07 2706 1707 46066 9533 97.6 1.336
-05.0 88 38.48 2732 1740 47428 9620 97.9 1.318
-04.0 88 38.88 2757 1773 48828 9704 98.2 1.300
-03.0 89 39.29 2783 1806 50267 9785 98.4 1.283
-02.0 90 39.69 2809 1839 51746 9863 98.7 1.266
-01.0 91 40.10 2834 1873 53268 9937 98.9 1.250
+00.0 92 40.50 2860 1907 54833 10008 99.1 1.234 ! Near Maximum !
+01.0 93 40.91 2885 1941 56442 10076 99.3 1.218 ! Near Maximum !
+02.0 94 41.31 2911 1975 58097 10140 99.4 1.202 ! Near Maximum !
+03.0 95 41.72 2936 2009 59799 10201 99.6 1.187 ! Near Maximum !
+04.0 96 42.12 2961 2044 61550 10258 99.7 1.172 ! Near Maximum !
+05.0 97 42.53 2986 2079 63352 10312 99.8 1.157 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 5% relative to nominal value:
+Ba 92 40.50 2921 1989 59409 9921 99.9 1.191 ! Near Maximum !
Data for burning rate decreased by 5% relative to nominal value:
-Ba 92 40.50 2788 1813 50286 9978 97.3 1.283

 

[Rmitch223]

interesting, where did you pull that information from?

 

[FOTIS]

Quickload.....

 

[Rmitch223]

Ive worked up from 37gn to 40gn and the rifle is shooting very accurately with 40gn. I'm not sure I will push it anymore. I may try 40.5 and 41gn in the future but right now I'm pretty happy. Shooting 1/2" groups at 100yrds now and 1" groups at 200yrds. I'm very curious as to what velocity I'm getting with this load. Gonna have to get a chronograph asap.

 

[onesonek]

I agree with Doc's post, and will throw in the test set up as well. It don't take much difference in the test chamber, yet still be in spec., to change start and max load recommendation.

"Ive worked up from 37gn to 40gn and the rifle is shooting very accurately with 40gn. I'm not sure I will push it anymore. I may try 40.5 and 41gn in the future but right now I'm pretty happy. Shooting 1/2" groups at 100yrds now and 1" groups at 200yrds. I'm very curious as to what velocity I'm getting with this load. Gonna have to get a chronograph asap."

Just keep in mind, accuracy come first and foremost,,,right behind safety. An extra .5-1 grian adding maybe a 100 fps may or may not be better in that accuracy dept.. But as suggested also, I wouldn't push the upper end of data to much, until you are sure of your experience, in knowing what you see and feel in pressure signs.
And for what it's worth, there are a few I run out near top end, I admit. But, if not really needed, I prefer to back off a .5-1 gr. from that. It's just much easier on the gun and brass life. Angain, accuracy is most important. If I need more than what that load and rig is capable of, well, then a get a different setup altogether.

 

[Rmitch223]

The 105 Amaxs shoot great in my 700 SPS-V using Retumbo, Win brass, and Fed 210M primers. Good luck!

Can you please list your most accurate charge weight for this load?

What charge weight did you start your workup with and how high did you go?

 

[Rmitch223]

I found two pounds of H4350 yesterday locally. So im starting a new load work up.

What charge weight do you recommend I start my workup at?

My Hornady manual shows a starting charge weight of 38.3gn and a max of 41gn.

Hodgdon's data online shows a starting charge weight of 35gn and a max of 37.5 so I'm a little confused as to why they are so much different.

Once again I'm loading for the 105amax in Lapua brass seated at 2.800" OAL with Federal 210M or CCIBR2 Primers.