.243 Win. Load - 105amax - Expereinced Suggestions Needed

[Ryan M.]

I just recently got into reloading about 6 months ago. During that time all I have loaded for is my .243 Win.

Over that time I have put together a fairly accurate load.
105amax
40gn of IMR-4350
Federal 210M
Seated at 2.800" OAL .020 off the lands.
Lapua Brass

I'm looking to get away from IMR-4350 because of its temperature sensitivity.

What powder(s) would be best for this load?
H4350?
H4831sc?
H1000? with a magnum primer?
Retumbo? with a magnum primer?

Another powder not listed?

Or stay with the IMR-4350 because my load wont have any pressure spikes come summertime(90 degree plus temps here in Oklahoma)? I understand that IMR-4350 is temperature sensitive, but since I worked up this load in the winter months would I have a pressure issue in higher temps or is it not that temp sensitive?

Here is my latest target with my current load, the two impacts in the upper right were sighters. I had just put on a Vortex Viper PST. The impacts in the center is a five shot group at 100 yards.

The Rifle - Rem. 700 SPS Varmint - 26" 9.125 twist barrel.

Any opinions would be appreciated.

Thanks alot,

Ryan

 

[civil82]

I've only shot H1000 with 243 Win and 107SMKs. Never needed a mag primer for any charge of H1000.

 

[284driver]

You wont really know you're going to have pressure problems with that combination in the summer til the temps start warming up. Do you know if you are pushing the upper limit with that charge right now? If it shoots awesome for you, keep on keeping on. If primers start flattening as it warms up, back off a half grain and try it. Just watch for signs. Most of the time your rifle will let you know when things are amiss.

 

[1holeaddict]

Dont fix what aint broke. Looks like your pretty close on a load and like said above tune what you got and watch for signs as the temp warms up. If your close to the upper limit now then start backing off and see how she shoots I shoot RL22 in two of my 243wins with great results and H4350 in the other. Good Luck and be careful

 

[K22]

I second the motion, if it ain't broke - don't fix it. IMR-4350 is one of the best, if not the best powders for the 243 especially with heavier bullets. I've been using it for many many years in the 243 and never had any problems with it.

Extreme temperatures can cause pressure surges even in the so called "temperature resistant" powders." The simple solution is not to expose them to direct sunlight or pack them in a thermal barrier container in extreme conditions.

H4350 is suppose to be more temperture resistant so you could try that if you're really stressing out about IMR 4350 but it may shoot differently.

I've used Varget for many years in my 223 and 308. Its one the "extreme extruded" powders and it suppose to be highly temperature resistant. However I've always had to make some minor scope setting changes from winter to summer. For one thing, the air density is considerable different in these seasons which will also have an affect of point of impact.

The one type of powder that I have had trouble in very hot tempertures, 90 degrees and above is ball powders, namely H380 and H335.

 

[TimP]

I started my load development with IMR-4350 and was able to find a very accurate node at a MV of 2880 with 37.5gn behind 115gn DTAC's. I had read that the 115gn DTAC was most accurate between 2950 and 2975 fps. So I tried H4350 and VV N165 and was able to reach those velocities but did not achieve the accuracy of my IMR-4350 load.