IRM-4350 vs H-4350

[charles p]

I just loaded 20 rounds for 280 with 140 grain bullets and CCI large rifle primers.  I didn't notice that my loading source listed H-4350.  I used IMR-4350.
Years ago I loaded some 7mm Rem Mag with IRM 4831 using an H-4831 recipe.  I was at max load for the H and the IMR was too hot.  Am I going to have problems with the 4350 powder swap or not?
Some say 280 listings are often on the mild side to accomodate the autoloader use.  Is 55 grains of IMR-4350 going to be OK?  It's is far from a full case.

[AtlLaw]

I think, as if anyone cares what I think..., that it's to close to call so err on the side of caution.      Especially since you asked if they would be okay which means to me you haven't tried that load in your rifle before.
 
Heck, it's only 20 rounds!      Tear 'em down and start over!   

[twoshooter]

That is pretty warm. Two Lyman books and a Hornady book show 54 gr of IMR 4350 as max. If you are shooting a very strong action bolt, you will probably be ok. Loads I used 40 years ago would have your hair stand on end today. That being said, what would be the value of shooting them? If they do well, are you going to continue to load them that hot ? It sounds like you are working up a load for your gun not just reloading a batch of your favorite recipe, so why not start in the middle. If you load hotter and it improves, fine, if worse, try loading lighter. This is not about the most speed and foot pounds, it is about being within a certain range and then delivering it on target.  I think I would pull 'em, but its your dime.

[sr sawyer]

Had a .243 Winchester with a very tight chamber and it pierced a primer with a load that was two grains or more under max in all the books.  Pull 'em and start over.
 
Ken

[Lloyd Smale]

not to be critical but its one of those things that if you have to ask you shouldnt be doing it. Ive loaded 100s of lbs of imr and hod. 4350 and 4831. Yup theres a bit of differnce in burning rates and youll find theres differnces in burning rates comparing the same powder lot to lot. Bottom line is if you stick to a loading manual (like you should be) there close enough that your not going to get into any trouble substituting one for the other. If like it looks your allready exceding the max load in your manual you can run into trouble just substituding a differnt lot number. When i was a beginning handloader I too did stupid things like working up loads till primers flattened and then backing off a grain (sometimes) Thing is i never saw a deer that knew the differnce in that extra 100 fps. Anymore if i want a 7mm bullet to run at 7mag velocitys i put the 280 back in the safe and grab a 7mag. If thats not good enough i grab the 7stw. Bottom line is your 280 pushing a 140 at even 2700 fps is going to kill any deer you stick that bullet into the boiler room of.

[charles p]

I tend to agree with the advice you fellows have provided, though if you Google this topic, there are about three posts that show this exact load.  Think I'll pull the bullets and drop back 2-3 grains.  At age 66, I'm not about speed anymore in anything I do.  Can only think of one thing that has gotten quicker as I've grown older, and the wife don't seem to mind.

[shot1]

I have always had great accuracy with the suggested accuracy loads out of the Sierra manuals. The 4th edition list for the 280 Rem with 140 gr bullets 52.8 grs IMR 4350 with Remington cases and Remington 9 1/2 primers for 2800 fps. They have a suggested hunting load which is the MAX load with 54.4 grs IMR 4350. By the way the best deer killing load I have ever seen uses a 154 gr Hornady Interlock cup and core bullet with 53.1 grs IMR 4350 which is the suggested accuracy load for 150 gr bullets in the 4th Sierra manual.  That 154 gr Hornady Interlock is just the old plain SP so don't get it confused with the SST or the Interbond. This bullet is the best 7mm bullet I have found for deer in everything from 7mm Rem mag down.

[Dave in WV]

You're a bit over max with 55gr of powder. Hodgdon has data online.

[LanceR]

IMR and Hodgdon powders are both marketed by Hodgdon who has a great library of data at Hodgdon.com.  There are pressure differences between the two powders and both have been reformulated over the years so cruise on over there and get some current data.

It is worth noting that load data changes over time due to powder formulation changes and other causes.  For instance, in the 1995 50th anniversary Sierra bullets reloading manual they made changes in a substantial number of loads due to discovering a long time error in the way they were determining data.

A different rifle or lot of cases, powder or primer can all change pressure so when working at or near max loads we should back off a bit and work back up if any changes are made.

Hodgdon's site shows 43.5 grains of H-4350 as the max load under a 140 grain bullet.  They don't show IMR-4350 but I'm sure that is more a matter of a fairly uncommon cartridge and not unsuitability.  Call them and they will likely have IMR-4350 data they will email you.

Looking at the 155 grain 30-06 data Hodgdon shows the H-4350 max charge as 62 grains and 47,500 CUP while the max IMR-4350 load is only 60 grains at 53,800 CUP.  I suspect that the same kind of pressure change might be happening in your case with the powder swap.

I think pulling the bullets is a good call.

BTW, the only powder I am familiar with that you can use how full the case is as a measure of safety is Trailboss which was formulated so that the maximum uncompressed charge that will fit in the case is safe.

Lance

[RevJim]

  Peace of mind is worth pulling the bullets, ha. I used 55gr of IMR 4831 and the Hornady 139SP in my first .280, a Ruger 77. It wasn't Max but it was a real killer on Texas deer/hogs. I later went to the Hogdon over IMR. I like the Hogdon Extreme powders just for their temperature stability, plus, I always got good accuracy. I also got terrific accuracy with R22, but it just wasn't as stable. I've loaded literally pounds of IMR 4350 in an old 1917 Enfield and friend's '06s, but this was in the milder Texas climate. I found I could work up a load in the hot summer, and later, the fall/winter never got that cold to make any difference in velocity. No doubt that the IMR powders are great, I just shoot from 100+ in summer here in Utah, and close to zero in the late winter! That's a big range, ha. Good luck to you and congrats on a great cartridge.

[Ron T.]

I just loaded 20 rounds for 280 with 140 grain bullets and CCI large rifle primers.  I didn't notice that my loading source listed H-4350.  I used IMR-4350.
Years ago I loaded some 7mm Rem Mag with IRM 4831 using an H-4831 recipe.  I was at max load for the H and the IMR was too hot.  Am I going to have problems with the 4350 powder swap or not?
Some say 280 listings are often on the mild side to accomodate the autoloader use.  Is 55 grains of IMR-4350 going to be OK?  It's is far from a full case.

*******************************************************

You're gotten some excellent advice by those who posted prior to this post... I'd listen to what they're saying.

I checked a couple of my reloading manuals for IMR4350 as well as H-4350 and found that you are about 1.0 grains over the MAXIMUM SUGGESTED LOAD recommended by well-known, pubished reloading manuals.

Is it safe to shoot... probably yes, but my 50 years of reloading experience sez that the load probably won't be all that accurate and so, you're just wasting expensive bullets and expensive powder to say nothing of the cost of the primers you'll waste in shooting those reloads.  Then, too... you'll be beating up your rifle as well... not a very good idea, is it?

A better choice would be to take the cartridges apart... saving the powder, bullets and primers.  RCBS makes a hammer-like tool for doing the job... I think the cost is about $10 or so and works like a charm... saving both powder and bullets to be used again.  This RCBS tool is one of those "must have" tools.  You can 'most likely find it at your local gunshops.  It sorta looks like a pale green plastic hammer.  I've had and used mine for the past 20 years or so.

You can save the primers simply by removing the primer punch out of your re-sizing die and running all the empty cartridge cases through the resizing die to re-form the neck down to the point where it will grip the bullet securely.  I.E., just neck-size those cases and load the same powder (but less of it) and the same bullet back into the cases AFTER you've neck-sized the case.

You can neck size the cases merely by turning the resizing die out a turn or so in your reloading press and locking it down.

Is it a pain-in-the-patootie?  Yes. 
Is this a safety issue?  YES!
Should you absolutely take the cartridges apart and empty out the powder and bullets?  DEFINITELY!

'Nuff said...


Strength & Honor...

Ron T.