IMR 4350 & H 4350, the same?

Pheroze

AH ambassador
Joined
Jul 6, 2013
Messages
5,050
Reaction score
8,219
Location
Ontario
Media
96
Articles
25
Hunting reports
Africa
1
USA/Canada
6
Member of
OFAH, DSC
Hunted
South Africa, Canada, USA
Hi,

I have been developing a load for the '06 using IMR 4350. I can only get H4350 to replace the 1lb container I have (stocking up now). The fellow advised they could be swapped grain for grain. I am not so confident. Anyone know the relationship?
 
Very close but not the same. Just because of lot to lot variation, I would not immediately swap grain for grain. You should definitely back off from your established load for safety. From there presume you're redeveloping your load for the particular caliber and bullet. Hopefully the load will be close and maybe even the exact same weight as the IMR version.
 
I have never found them to be the same.

Tim
 
I would start going to a different store if the person at the counter told me that you could swap them grain for grain. That is a big problem waiting to happen.

As for a relationship between the two, Hodgdon owns IMR and manufactures IMR 4350 but that doesn't make it the same as H4350. They have similar burn rates but are not interchangeable.

This is where you need to look at the loading in a reloading manual, if the manual that you are using doesn't list both powders for your bullet choice check the IMR and Hodgdon sites on line to see what they recommend.

You will also find that Hodgdon 4350 is an 'Extreme' powder and will give consistent performance over wide ranges in temperature.
IMR 4350 isn't, and you'll get different performance n hot and cold conditions.
 
Thanks guys. I wasn't comfortable with the advice. I have several manuals but they are not consistent. For the Hornady BTSP 180 gr interlock the published maximum is 54.5gr imr 4350. In the Lee manual the published max for 180gr is 56.5. I stuck to the hornady data and stopped at 54.5gr and have it going about 2620 fps (22" barrel). This gave my best groups of those tested. But the hornady manual does not have H4350 for the 180gr and Lee publishes 57.5 never exceed. I am going to email Hornady to see what they say the max load for H4350 is.
 
Odds are Hornady will refer you to purchase their newest manual instead of giving you any load data for that bullet.

Hodgdon list 57.5 grains of H4350 as the max for a 180 grain bullet with 52 grains being the starting load.

http://www.hodgdonreloading.com/data/rifle
 
Strange that the hornady manual has a max that is two grains less for IMR than Lee.
 
Strange that the hornady manual has a max that is two grains less for IMR than Lee.

You will find when you open up any 2, 3, 4, or how many other manuals that the max loads will very seldom be the same. It all depends on what they are using to measure the pressures of the loaded round and how they are doing it, barrel length, temperatures and other variables.

That is why they tell you to work up to a max load for your firearm and to never start with the max load listed.
 
Echoing the "similar but not the same" chant. Supposedly H4350 is rated slightly slower than its IMR brother. But my last pound of H4350 was ever so slightly faster than my 15 year-old pound of IMR4350 and my newly purchased pound of IMR4350. I suspect the lot-to-lot difference of the H product is no more than the lot-to-lot difference of the IMR product but there's no reason to tempt fate at any stage of the reloading process.
And then there is AA4350, which gets little mention.
 
They are not the same and you really should get a current loading manual and develop your loads off the starting recommendations therein.
 

Forum statistics

Threads
53,985
Messages
1,142,321
Members
93,342
Latest member
Warren03T
 

 

 

Latest profile posts

Cwoody wrote on Woodcarver's profile.
Shot me email if Beretta 28 ga DU is available
Thank you
Coltwoody@me.com
Pancho wrote on Safari Dave's profile.
Enjoyed reading your post again. Believe this is the 3rd time. I am scheduled to hunt w/ Legadema in Sep. Really looking forward to it.
check out our Buff hunt deal!
Because of some clients having to move their dates I have 2 prime time slots open if anyone is interested to do a hunt
5-15 May
or 5-15 June is open!
shoot me a message for a good deal!
dogcat1 wrote on skydiver386's profile.
I would be interested in it if you pass. Please send me the info on the gun shop if you do not buy it. I have the needed ammo and brass.
Thanks,
Ross
 
Top