confirm a charge for .243 Win and IMR 4064

[thomis]

My old Lyman book says 36.5 grains of IMR 4064 is max load. This manual is from the 70's. I don't know how current this is or if IMR 4064 has changed much since then. I've been shooting loads off of loaddata.com with charges of
35.5
35.7
35.9
and 36.0
with no pressure problems/signs and accuracy continues to improve the higher the charge. I'd like to keep trying to eek up to 36.5 by tenth of grain increments if I can get confirmation on the max of 36.5
Many thanks,

oh, sorry, it's a Hornady 100 grain Spire Point bullet (cause I have a bunch of them)

 

[rcmodel]

Check on Hodgdon website for current IMR data.

http://www.hodgdon.com/basic-manual-inquiry.html

rc

 

[thomis]

I did check the hodgdon website, but their 100 grain bullet is a Speer BTSP.
I'm using a Hornady flat base spire point.
Is there much of a difference? I try and use caution when I see these discrepancies.

 

[rcmodel]

Hornady #6 manual says 34.2 is MAX.
Lyman # 49 doesn't list IMR-4064 with anything heavier then a 90 grain bullet.

IMO: It's really too fast a powder for that heavy a bullet.

rc

 

[Ky Larry]

The Hornady 8th Edition manual lists 31.0-34.2gr of IMR-40964 for 100gr Hornady SP flat base bullet (#2450). Listed C.O.L. is 2.630".

 

[ArchAngelCD]

Hot off the presses, from Hornady #9
Hornady 100gr InterLock SP 2.630" COAL (just like said above)
IMR4064
31.0gr 2600 fps
32.6gr 2700 fps
34.2gr 2800 fps MAX

IMO IMR4064 is on the fast side for use in the .243 Win. Three slower powders are reported to generate 2900 fps and 10 others will push that bullet to 3000 fps. Your powder is listed as generating the least velocity not that bullet speed is everything but of the 14 powders listed it is the only one that delivers only 2800 fps. Several sources I scanned list H4350 and H4831 as possibly most accurate for your combination.

 

[thomis]

My Grandfather told me years ago (and goes along with the old myth) that the faster powder was best in my .243 Mohawk 600 (18" bbl). I can't blame him for not knowing better because it was the widely accepted "truth" at the time. I know this myth has since been debunked and discussed often here.
But the fact remains that it is very accurate in my rifle and.... I have a whole helluva lot of it.

I don't know why Hornady is so conservative with the charges for IMR 4064 here. Hodgdon's published data lists a max charge of 36.5 grains:

100 GR. SPR BTSP IMR IMR 4064 .243" 2.650"
33.0 2672 42,200 CUP 36.5 2902 51,100 CUP

I've worked my way up to 36.0 grains with no pressure problems/signs and accuracy continues to improve the higher the charge. I'm considering going on up to 36.5 a tenth of a grain at a time.

But thanks, by the way, for sharing the Hornady manual info.

 

[kelbro]

That powder has worked very well for me with 100gr bullets.

 

[ArchAngelCD]

My Grandfather told me years ago (and goes along with the old myth) that the faster powder was best in my .243 Mohawk 600 (18" bbl). I can't blame him for not knowing better because it was the widely accepted "truth" at the time. I know this myth has since been debunked and discussed often here.
But the fact remains that it is very accurate in my rifle and.... I have a whole helluva lot of it.

I don't know why Hornady is so conservative with the charges for IMR 4064 here. Hodgdon's published data lists a max charge of 36.5 grains:

100 GR. SPR BTSP IMR IMR 4064 .243" 2.650"
33.0 2672 42,200 CUP 36.5 2902 51,100 CUP

I've worked my way up to 36.0 grains with no pressure problems/signs and accuracy continues to improve the higher the charge. I'm considering going on up to 36.5 a tenth of a grain at a time.

But thanks, by the way, for sharing the Hornady manual info.

If loads made with IMR4064 are accurate in your rifle there's no doubt you should use it, hands down. Just be careful going higher than the Hornady data with a Hornady bullet, even though Hodgdon shows a higher charge. The Hodgdon data was developed with a Speer BTSP bullet, not the Hornady bullet you are using. I agree the Hornady and even the Speer data seems to be anemic compared to the Hodgdon data but I have to believe the bullet company know best with their bullets. You sound like you are careful so do what you think is safe.

 

[joed]

I don't know why Hornady is so conservative with the charges for IMR 4064 here. Hodgdon's published data lists a max charge of 36.5 grains:

You just hit the reason I no longer spend a penny on Hornady manuals. I can understand a cartridge or two showing lower load data then other sources but Hornady is low on almost every cartridge.

And don't buy into the explanation that the powder burns faster now. I have a friend that is a chemist. His thoughts on this are that if the powder burn rate changed that much than the powder designation would change.

The last straw was a load they showed as max in the .22-250 produced 3200 fps in my rifle. Now I know someone is going to say "but all rifles are different". Yes, but 500 fps different?

 

[sdhunter]

my dad bought his first .243 in 1973, along with a loading manual and reloading kit. He has loaded 100gr hornady flat base soft points since then with 36 grns of 4064, the load is a tack driver. When i bought a new reloading manual and seen that the new max load was 34 grains he said well son, i have shot several thousand 36 grain loads out of that gun since the 70's so if something was going to go wrong it would have happened by now lol. you just cant teach an old dog new tricks i guess.

 

[azjohn]

I have Hornady Vol2. It lists 37.8 grains as a max load at 3000 fps for 100 grain spire point; and a seating depth of .501

 

[richie]

The Sierra 5th edition reloading manual lists as recommended hunting load 36.2 grains of imr-4064. Its also there maximum load. for the 100 spire point.

 

[thomis]

Since I originally posted this, I have worked up to the 36.5 charge of IMR 4064 using the 100 grain Hornady SP bullet seated at 2.65". There are no high pressure signs and case expansion is normal. I'm stopping there, though. This load gives exceptional groups out of my hunting rifle. Better than H4831, H4895 and Varget.
Thanks for all your help and input.

 

[GooseGestapo]

The design of the bullet makes a lot of diffence in the pressures it developes.
The Hornady's use a "tangent-ogive" and combined with a flat-based bullet gives a longer bearing surface in contact with the bore. This increased friction raises the pressures, especially with a faster burning powder such as IMR4064 in the .243.

Be extreamly careful with the .243. A friend ruined his Rem Mod788 using a "starting load" of H4831 and a Speer 105gr flat-based bullet. Problem was, he didn't consider that he was using Federal brass instead of Winchester. The brass case head was so expanded he damaged the bolt and extractor removing the fired case....
The .243 and 7mmRemMag both have reputations for pressure excursions when components are mix-matched.
It's a well deserved reputation !!! (not a "slam" against the cartridges as I have rifles/reload for both, but I do "respect" their idiosyncrasies....)