.243 OCW test using H4350 UPDATED

P

poke5353

Full Member
Full Member
Minuteman
Jan 15, 2009
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Central Arkansas
#1
Ok first off this is the first OCW type test I have ever done and this is the first day I have ever shot this rifle. I loaded hornady 105gr bthp book shows Max load for 243 with H4350 is 37gr. That is where I started considering I have read several posts and opinions on going up to 42gr with H4350 with no signs of pressure. I started with the 37 and worked my way up to 41.5 in .5gr increments. All loads were set at 2.78 OAL. Something happened to the 37 and 37.5 loads. They were really spread out and I couldnt find all the rounds. All loads showed slight ejector marks and bolt lift gradually increased but not engough to cause me to stop. I fired 5rds from each load. I did not have a crono to test velocity but I will soon. I am thinnking that I should go with the 40gr load. Any opinions or suggestions are welcome.

<span style="color: #FF0000">UPDATE</span>

Went back to the range with some more rounds. I loaded at the same OAL and the same bullet. I started at 40.3 and went up .3gr to 42.1. Still have the same extractor marks bu that is the only sign of pressure I have seen. I am not too worried about that. I am thinking about taking the 41.8 load and working on the OAL with it to gain accuracy. What do ya guys think?


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#2
Re: .243 OCW test using H4350 Need opinion

i think i'd play with both the 40 and 41 a little and try diffrent setting depth's and a crono would be nice also. the vertical string on the 41 might have been you both look good to me.
 
#6
Re: .243 OCW test using H4350 Need opinion

You are not doing an OCW test....

You are just doing a regular test, looking for a good group, and trying to call it OCW.

.5 grain increments are WAY too damn large, especially for a .243, per the OCW principles. How in the hell do you expect to see your nodes form and dissipate?

Five round groups are basically useless in an initial OCW because, unless you are taking the extrordinary time to let the barrel cool, you are influencing the results with barrel heat. I've done initial OCW's with just one round per increment with a quality barrel/trigger, it's just that easy. 3 rounds is more than sufficient shooting round robbin...save your five round groups for proof testing what you find with the initial tests, or final seating depth adjustments.

Your test is showing you exactly zero about your barrel harmonics..........
 
#7
Re: .243 OCW test using H4350 Need opinion

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">You are not doing an OCW test....

You are just doing a regular test, looking for a good group, and trying to call it OCW.

.5 grain increments are WAY too damn large, especially for a .243, per the OCW principles. How in the hell do you expect to see your nodes form and dissipate?

Five round groups are basically useless in an initial OCW because, unless you are taking the extrordinary time to let the barrel cool, you are influencing the results with barrel heat. I've done initial OCW's with just one round per increment with a quality barrel/trigger, it's just that easy. 3 rounds is more than sufficient shooting round robbin...save your five round groups for proof testing what you find with the initial tests, or final seating depth adjustments.

Your test is showing you exactly zero about your barrel harmonics.......... </div></div>

+1

.2 or .3 increments will work best.
 
#8
Re: .243 OCW test using H4350 Need opinion

Thanks for the input. The reason I done 5rd groups is because I already had them loaded. I waited 2 min between every shot and it was a round robin. Yet again the .5gr was bc I already had them loaded and then found info about ocw testing.
 
#9
Re: .243 OCW test using H4350 Need opinion

8b68d0f9.jpg


H4350 - 42grains
2.72 COL
70 degrees
585'
3110fps

I see the marks on you case. I am not an expert reloader. How is it that my load at 42.0 grains shows no sign and/or stressors on the case and poke's does?

My rifle:
.243 Krieger #5, tight bore, 1/8 twist
standard 243 chamber
 
#11
Re: .243 OCW test using H4350 Need opinion

Poke,

In fairness, I have another group w/three touching and two about an inch to the right touching and it drives me a little crazy. I believe it is me (my breathing) and not the rifle. I have never done the OCW test. I use to get crazy/silly w/my reloading and then went back to the basics. What kind of group is the rifle shooting? How fast can I push it without any issues. This is where I am at now in this process (so far).

Shooting was done prone w/bag.

 
#13
Re: .243 OCW test using H4350 Need opinion

Poke,

Your COL could be a concern? 2.76 is what standard per Hodgdon. I have another reloading manual that states 2.6(something) for the 105 Amax - can't remember. The way that I came up with mine was to measure to the O-give and took off a couple hundredths. Mine is a standard chamber like yours. So, you might want to check that out.

I don't like the marking on the bottom of your case. I know some comp people that dont mind hot rounds because they are going to chuck the brass. But I want to use my brass as many times as possible.
 
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