Discussion in 'The Ammo & Reloading Forum' started by TheGunClinger, Jun 18, 2012.

  1. TheGunClinger

    TheGunClinger Well-Known Member Supporting Member

    Quick question, what are the differences between IMR 4895 and H 4895?
  2. JLA

    JLA Well-Known Member

    Feb 26, 2007
    Heart Of Texas
    H4895 is slightly faster. They have the same applications but data in not interchangeable.

  3. Hammerslagger

    Hammerslagger New Member

    Jul 30, 2009
    Very good question, today. Today, Hodgdon owns both brands and I cannot really believe that they are likely different propellants today. However, THIS IS A QUESTION FOR HODGDON TECH PERSONS, TODAY.

    The account below does not dot every "i" or cross every "t"; but it is basically accurate.

    Originally 4895 was made by DuPont primarily for the U S Government, possibly Remington (which DuPont owned), and maybe some for Federal Cartridge Co. It (4895) was designed to power the US M1 Garand Rifle which needs about 5000 psi port pressure (within very narrow limits) to cycle properly.

    After WW II, Bruce Hodgdon purchased 50,000 pounds of U S Government surplus 4895 and went into the powder business. The surplus powder was not made to commercial tolerances typically needed for retail sales to handloaders which is called "Canister Lot" grade powder. However it was uniform enough in lot to lot pressure performance (because it was designed for the Garand's narrow limits gas system) to be safely sold with conservative loading data supplied by Hodgdon. This may be the reason one still sees milder loads for H4895 vs IMR 4895, today. A good bit of old surplus 4895 is still in handloader hands. This is a good question for Hodgdon, today,

    Now, come forrward about 20 to 30 years. Hodgdon's sales of surplus 4895 was such a success that in the late 1960's or early 70's Dupont started making and selling 4895 commercially using their IMR (Improved Military Rifle) trademark. There was enough potential pressure difference between the Canister Lot DuPont IMR and the Hodgdon surplus 4895 to justify different loading data that was not interchangeable.

    Now, come forward to the more recent times of the last 15 years. DuPont sold their companies that were based on things that went "bang" or "boom". Olin did the same with propellants for handloading. The "three headed dog" bought Remington, Hodgdon bought or leased IMR and Winchester powders.

    Today a handful of plants make all of Hodgdon's products. Some exact same propellants are marketed by Hodgdon under at least two of their brand names. I would infer that recent commercial production 4895 is likely one of them; BUT THIS IS A QUESTION FOR HODGDON AS IT IS SAFETY RELATED.

    Hope this was informative.
    Last edited: Jun 18, 2012
  4. TheGunClinger

    TheGunClinger Well-Known Member Supporting Member

    Most informative indeed. The reason for asking is that I have some of both and want to use one or the other for my 45/70 Gov. rounds. Depending on projectile, data states use IMR-4895 and on other projectiles data says to use H-4895, and then again on other bullets it gives data for either powder. I am using the Lyman 49th, the Lee 2nd ed. and the Speer #12 and #14 manuals.
    Thanks guys!
  5. steve4102

    steve4102 Former Guest

    Jan 27, 2006
    Regardless of the fact that Hodgdon is the distributor for both IMR and H 4895 they are NOT the same powder. IMR Powders are manufactured in Canada and Hodgdon H 4895 is manufactured in Australia. Two completely different powders and load data is not interchangeable.

    The only thing these two powders share is a similar name(number), They Are Not The Same.
  6. Hammerslagger

    Hammerslagger New Member

    Jul 30, 2009
    Thanks for the info, steve4102.
  7. myfriendis410

    myfriendis410 Member

    Mar 30, 2011
    Lompoc California
    What exactly are you trying to load in the 45/70? and for what gun?
  8. TheGunClinger

    TheGunClinger Well-Known Member Supporting Member

    Marlin 1895 SBL Guide gun. I started out loading 405g JSP's. Lyman manual says H4895 start 49g, also Varget start 50g. Lee data says 48.1g start IMR4895. I went with the H4895 and then some with Varget. Both shot well. Then I loaded some 400g JSP's using Speer data. H4895 start of 52g, and Lee data of start H4895 50g. I went with the Speer. Also shot well. I have some 300g JHP's that Lyman calls for start of 58g H4895 and 57g of IMR 4895. Tried them both. Got on paper but what a kick!I also bought a box of Laser Cast 405g FP's which I am using 50g Varget which is .5g over start according to Lyman. Thats all I have for now. Bullets for 45/70 are hard to find.
  9. Kevin Rohrer

    Kevin Rohrer Active Member Supporting Member

    Apr 9, 2010
    Medina, Ohio
    This means H4895 must be loaded upside down. :lmao2:
Similar Threads
Forum Title Date
The Ammo & Reloading Forum %#@&&@ IMR 4895 Feb 19, 2016
The Ammo & Reloading Forum IMR-4895 vs. H-4895 in .30-40 Krag Oct 17, 2015
The Ammo & Reloading Forum RG4895 Reloading data -- another Question Sep 20, 2014
The Ammo & Reloading Forum Reloading data on RG4895 Sep 10, 2014
The Ammo & Reloading Forum H4895 fizzle and no bang Aug 14, 2014