Sierra 243 load data

[Shootinsurveyor]

I have a Sierra PDF on my Ipad that say the accuracy load for the 107 SMK is 39.6 IMR-4350 at a velocity of 2800fps. The H4350 load is the same and is quoted as the max load. I have both powders, but have only loaded 243 with the H4350. Has anyone used or tried this load? I am thinking about whipping up a batch using the IMR 4350. I imagine my loads will have a little less velocity since I shoot a 20" barrel. Is there much difference between these two powders?

 

[jschroed]

Re: Sierra 243 load data

They are right next to each other on my Burn Rate Chart. As always you should start low and work up. I would not start with the full 39.6. I have had primers leak on my 243 at less then max. load. Be safe.

 

[Tripwire]

Re: Sierra 243 load data

Never assume anything.....

Published data is only a source of vague reference, at best...always back off and work up.

 

[Shootinsurveyor]

Re: Sierra 243 load data

I'm running 38 grains of h4350 with 105 Amax right now with no signs of pressure. The load actually feels a bit lethargic compared to the factory loads I have shot. I'll work up though. What is primer leak?

 

[Helmet]

Re: Sierra 243 load data

Just going by the Lee book and the Hodgdon/IMR/Winchester Reloading Data Center it looks like Retumbo would give you the biggest advantage for those heavy for caliber bullets. Plus, it's one of Hodgdon's extreme powders so it would be temperature insensitive like H4350. I know that doesn't answer your question, but I think Retumbo outperforms both of them for what you are doing.
http://data.hodgdon.com/cartridge_load.asp

 

[Fuzzball]

Re: Sierra 243 load data

<span style="font-style: italic">"..PDF on my Ipad that say the accuracy load for the 107 SMK.."</span>

Well, they said that was <span style="text-decoration: underline">their</span> 'accuracy load'; that's VERY MUCH different from saying it's "the" accuracy load. I suspect it has maybe a 5% chance of being really good in other rifles.

 

[Helmet]

Re: Sierra 243 load data

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body"><span style="font-style: italic">"..PDF on my Ipad that say the accuracy load for the 107 SMK.."</span>

Well, they said that was <span style="text-decoration: underline">their</span> 'accuracy load'; that's VERY MUCH different from saying it's "the" accuracy load. I suspect it has maybe a 5% chance of being really good in other rifles. </div></div>I have to agree with Fuzzball on this completely. I would like to add that since the load isn't going to be identical anyway I think you should go with what gives you the best performance and then tweak it until it becomes your rifles accuracy load. That way you can have the best of both worlds.

 

[boltgunluvr]

Re: Sierra 243 load data

H4350 meters much better than IMR version. The 20 in pipe places you at a crossroads. 243 Win really shines with very slow powders with very heavy bullets, but that 20 in pipe......I don't know. Please do not forget about H4831 or IMR4831. If you have any on hand, I think you may be have better results. I use H4350 & H4831 using 100gr Sierra flat base out of 24in & 26in pipes. The H4831 groups a little better for my 243, but it doesn't meter wirth a damn. H4350 meters much better than the H4831. I've never tried the SC version of H4831 because I like to get good load density. 243 Win is an overbore.

 

[armorpl8chikn]

Re: Sierra 243 load data

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body"><span style="font-style: italic">"..PDF on my Ipad that say the accuracy load for the 107 SMK.."</span>

Well, they said that was <span style="text-decoration: underline">their</span> 'accuracy load'; that's VERY MUCH different from saying it's "the" accuracy load. <span style="color: #FF0000">I suspect it has maybe a 5% chance of being really good in other rifles. </span></div></div>

That is what I love about statistics, 90% of them are made up on the spot.
I would disagree vehemently with your statement in red. If you had said 5% chance of being THE accuracy load in your rifle I would almost have to agree. Saying it has a 5% of being just a really good load? Well I have personally witnessed the Sierra accuracy load being very good in far more than 5%.

OP the H4350 may be very good in your 243. Try it before you put all your eggs in one basket. The powder at the top velocity spot in a chart means almost nothing. The one that lists the highest density means very little as well. There are many factors at play when a rifle load is developed. Sometimes a rifle responds well to high density and sometimes not. I have found most of my best loads at 95-100% density. The heavily compressed loads have rarely worked in any of my rifles and pistols.

 

[Shootinsurveyor]

Re: Sierra 243 load data

The load I run now is MOA out to 500yds which is as far as I have tried. It does leave a good bit of room in the cartridge which I have heard isn't good. It shoots as well as I can since I don't think I am any better than MOA myself. The Shilen Select match barrel I installed seems to shoot good with anything I put in it. I have a 8 twist so accuracy is great with the heavy for caliber bullets. I have figured my MV to be around 2750 using drops at distances in my ballistic calculator and real world testing.

 

[Helmet]

Re: Sierra 243 load data

I also like to fill the case as much as I can without compressing the load. H4350 is a great powder and it's what I'm using for 7mm08 right now. However, Retumbo or H1000 might allow you to fill the case better. I'm noticing in the Lee book that the 46 grain max load of H1000 is not listed as a compressed load. The 46 grain max load of H1000 is, however, listed as a compressed load in the Reloading Data Center. Because of this I'll bet that the 46 grain max load is right on the cusp of being compressed and probably fills the case quite nicely with both 105&107grain bullets which share the same load data (43-46gr).
As amorpl8chikn pointed out, heavily compressed loads are not ideal. I know that you would be able to fill the case with Retumbo without compressing the load, but perhaps H1000 would allow you to do this at the maximum load without compressing the load. H1000 is also a Hodgdon extreme powder. H4350 is very popular in 243, but because you are able to shoot the heavier bullets it will lose some of it's advantage to the slower burning powders.
As a side note, I think that running the heavy bullets in 243 like you are doing is a terrific setup.

 

[kylongshot]

Re: Sierra 243 load data

i run H4350 in my gun with the 105's and ive ran all the way to 43gr with no pressure but you gotta work up

 

[WyomingShooter]

Re: Sierra 243 load data

I am new to hand loading and just started working up a load for my .243 Win. The rifle is built on a Surgeon 591 action with a 24" Krieger barrel.

Present load averages 2767 fps:

Hornady 105 AMAX
Hornady cases
41.5 grains H4350
Federal 210M primer

I plan to increase the powder charge by .5 grain increments, watching for pressure signs and hoping for approximately 3000 fps.

Edit 6/29/2012

I believe the above chrono readings are in error. I today ran 42.0 grains H4350 with 105 AMAX and was averaging about 3094 fps. I will load additional rounds with 41.5 and chrono a second time.

 

[boltgunluvr]

Re: Sierra 243 load data

Twist rate???????????

 

[kylongshot]

Re: Sierra 243 load data

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WyomingShooter</div><div class="ubbcode-body">I am new to hand loading and just started working up a load for my .243 Win. The rifle is built on a Surgeon 591 action with a 24" Krieger barrel.

Present load averages 2767 fps:

Hornady 105 AMAX
Hornady cases
41.5 grains H4350
Federal 210M primer

I plan to increase the powder charge by .5 grain increments, watching for pressure signs and hoping for approximately 3000 fps.
</div></div>

i have a 8 twist 22" and i get 2950 with 41.5gr H4350

 

[WyomingShooter]

Re: Sierra 243 load data

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: boltgunluvr</div><div class="ubbcode-body">Twist rate??????????? </div></div>

1/8. Sorry I forgot to include that.