I am changing my rifle from a .308 to a 260 Remington. Looks like most people are loading for the 140's with H4350. After looking around H4350 is pretty hard to come by. Can IMR4350 be used with good results? Am I better off trying 4831 ssc or 7828 ssc or RL19 all of which seem to be more available than H4350? I am using this in a 28" barrel and trying to get enough speed to reach 1k. Any input would be very welcome.
Differences between H 4350 and IMR 4350
- Thread starter rocknut
- Start date
Jay Christopherson
Not An Admin
Well, they are two entirely different powders, so there's that. ;-) I've tried IMR 4350 in a few different calibers, but have not had good luck with it personally. Supposedly they have similar burn rates, but in my experience, not close enough to be a 1:1 substitute. Nor has the accuracy been there. I know other guys have had luck with it though.
I know some guys use RL-17 with good results. I think RL-19 will be too slow. Unless you are in a hurry, I'd keep an eye out for H4350. It's really not that hard to get ahold of, unless you are in desperate need.
I know some guys use RL-17 with good results. I think RL-19 will be too slow. Unless you are in a hurry, I'd keep an eye out for H4350. It's really not that hard to get ahold of, unless you are in desperate need.
Thanks for your reply. I kind of figured that was the deal. Just looking at Gunbot powder selection there are maybe 30 difference sources of IMR4350 and not 1 listing for H4350. If they were the same, they both have the same availablity. Nosler shows their accuracy load to be 44 grn of H4831. So maybe I can try that. I actually saw a couple of places to get Varget! Figures I would move to a even more allusive powder!
IMR is going to be a little hotter and more temp sensitive. dont accidentally load H4350 data with IMR 4350 powder and vice versa.
H4350 will show up again. Be patient and use what the most of us in the 6.5mm (260, 6.5creed, 6.5x47L) are using. I use H4350 in my 6.5 creedmoor tac rig.
In 260 rem, the 140gr bullets like the 142gr SMK, 139gr Scenar, 140gr hybrid, 140gr VLD, or the 140gr A-Max is what most guys are using. In my 26" barrel, I get 2830-2850 fps and I have about a 7.9-8.0 mil hold at 1K. You will have plenty of horsepower to get to 1K. In your 28" barrel, I would probably expect consistent 2850fps or a little bit more than this with H4350. I can gaurantee you that your will be dialing in a lot less wind and elevation than the 308 guys for the most part.
You can go H4831SC, but you will need a long drop tube and you will need to slowly drop that powder in to get it pack in so you dont go crunching powder during your seating process. You will also probably get slightly slower velocities with this powder. You will also need more powder to get that velocity.
if you want pure horsepower, RE-17 is the way to go. Watch out though as this is temp sensitive as well and the pressure creeps up on you fast so be careful on your load development and watch the pressure signs. You will easily be in the 2900+ fps world with this powder. Most of us dont use this because it is a little temp sensitive.
Varget will be a little too fast with 140 gr bullets. Maybe in the lighter bullets it might work though, but then you might be sacrificing BC on the bullet as the 140gr pills are good wind buckers.
H4350 will show up again. Be patient and use what the most of us in the 6.5mm (260, 6.5creed, 6.5x47L) are using. I use H4350 in my 6.5 creedmoor tac rig.
In 260 rem, the 140gr bullets like the 142gr SMK, 139gr Scenar, 140gr hybrid, 140gr VLD, or the 140gr A-Max is what most guys are using. In my 26" barrel, I get 2830-2850 fps and I have about a 7.9-8.0 mil hold at 1K. You will have plenty of horsepower to get to 1K. In your 28" barrel, I would probably expect consistent 2850fps or a little bit more than this with H4350. I can gaurantee you that your will be dialing in a lot less wind and elevation than the 308 guys for the most part.
You can go H4831SC, but you will need a long drop tube and you will need to slowly drop that powder in to get it pack in so you dont go crunching powder during your seating process. You will also probably get slightly slower velocities with this powder. You will also need more powder to get that velocity.
if you want pure horsepower, RE-17 is the way to go. Watch out though as this is temp sensitive as well and the pressure creeps up on you fast so be careful on your load development and watch the pressure signs. You will easily be in the 2900+ fps world with this powder. Most of us dont use this because it is a little temp sensitive.
Varget will be a little too fast with 140 gr bullets. Maybe in the lighter bullets it might work though, but then you might be sacrificing BC on the bullet as the 140gr pills are good wind buckers.
Thanks bsumoba. I wasn't actually thinking of using Varget in this rig, at least not with the 140's. It just seems to be in the same availability category-unobtainium. I've been able to get one pound of Varget in the last year for my .308. I've worked up loads with all kinds of different powders due to the shortage. Things seem to be getting somewhat better, but it is still challenging out there.
My reloading book also shows that IMR 7828 looks to be the fastest load listed, but it is a compressed load. Also I've found that generally loads near max aren't the most accurate. I'm hoping to find a high node that will let me get to 2800 fps. That would let me reach 1000 yards with 5 moa less elevation and almost a minute of drift at 10 mph than my .308 load.
My reloading book also shows that IMR 7828 looks to be the fastest load listed, but it is a compressed load. Also I've found that generally loads near max aren't the most accurate. I'm hoping to find a high node that will let me get to 2800 fps. That would let me reach 1000 yards with 5 moa less elevation and almost a minute of drift at 10 mph than my .308 load.
IMR 4451 might be interesting. It has almost the same burn rate as H4350. IMR max load shows only 39 grains, I usually look for something around 95 to 100% fill capacity. I do like the copper fouling eliminator additive they use though. I used CFE 223 in my .308. It burns really clean and I got excellent velocity out of it. Thanks for the suggestion. Sounds like it's pretty insensitive to temp changes as well.
I'll probably try Lapuas and Bergers. They do seem to make the most consistent bullets out there. My .308 doesn't seem to like the 155 scenars much, but hey; it will basically be a different rifle with the new barrel in .260.
I'll probably try Lapuas and Bergers. They do seem to make the most consistent bullets out there. My .308 doesn't seem to like the 155 scenars much, but hey; it will basically be a different rifle with the new barrel in .260.
Again they may not be easy for you to get hold of, but I'm using N160 and N165 in my 260 Rem. Regards JCS
All the above seems to hold true with my findings too. If you're careful RL17 will get you the speed. Usually the same speed as H4350 with one grain less powder.
4831sc works for a lot of guys also. You do have to stuff a lot of it in there to get the speed though. I was never able to get it to shoot how I wanted though.
FWIW 43.5gr of H4350 gets me 2900fps out of a 27" barrel. It's at the top of acceptable pressure.
4831sc works for a lot of guys also. You do have to stuff a lot of it in there to get the speed though. I was never able to get it to shoot how I wanted though.
FWIW 43.5gr of H4350 gets me 2900fps out of a 27" barrel. It's at the top of acceptable pressure.
Thanks Geno. That confirms some of my thoughts. It's going to be hard to fit 45.7 of H4831 (hodgdon data) and a 140 grain bullet in the case, even with the H4831ssc. Good to hear your getting 2900 out of your rig. I am hoping to get 2800 fps in an accuracy node without signs of pressure. I'm leary of RL17 as I will be developing my load this winter, then have to shoot in 90 degree heat this summer. I'll keep looking for H4350 I guess.
Thanks to a PM from one of the fine gents on this board, I now have 4 lbs of H4350 on the way. I also got a couple of pounds of H4831sc to try as well. Thanks again for all the great feed back from the members here! I just received my Criterion barrel today. It is finished very nicely. I like how they rolled the caliber and twist into the shank. Very clean. I'll post results once I get some brass & load some rounds.
WyleWD
Silver $$ Contributor
About 6 or 7 years ago I worked up loads for one of my 6xc's using both H4350 and IMR 4350. At that point in time we didn't see much difference between the two, both accuracy and speed wise. Toss a coin close. I thought the IMR burned a little cleaner but seemed harder to find in larger quantities so I went with H4350 and still use it.
All that being said, the H4350 lot that I bought last summer after it once again became available burns MUCH dirtier than the lots I have that were made prior to the "shortage". ??? Still trying to figure that one out. WD
All that being said, the H4350 lot that I bought last summer after it once again became available burns MUCH dirtier than the lots I have that were made prior to the "shortage". ??? Still trying to figure that one out. WD
A year or so back I read a magazine article regarding H4350 vs IMR 4350. I don't remember the exact details at the moment, but wrote them down and keep those notes in my powder locker. It seems that there are two different versions of IMR 4350. Since I have some powder more than 10 years old, I found I had both types. One is called "Dupont IMR" and the other is only called "IMR". Only one is produced today and I forget which it is off the top of my head. According to the article, the earlier one was definitely not the same as H4350. But the newer one was supposed to be produced on the same line as H4350 today and they are sold under the two different brands now. One of the companies purchases it from the other according to this article. I am not stating this as a fact, but only repeating what the article said.
In my 6.5 Creedmore, with a 28" barrel, I shoot 1000 yard matches. Doing load testing at 200 yards, I have shot several literal single hole 5 shot groups. It runs 140 Bergers at 2830. I have tried both powders (H4350 and the newer IMR4350)and in my rifle they shoot the same to the point I could not see any difference in accuracy or velocity over a Magnatec II Chrono. I keep the batches of cartridges separate of course, but I could not see any difference on the targets.
In my 6.5 Creedmore, with a 28" barrel, I shoot 1000 yard matches. Doing load testing at 200 yards, I have shot several literal single hole 5 shot groups. It runs 140 Bergers at 2830. I have tried both powders (H4350 and the newer IMR4350)and in my rifle they shoot the same to the point I could not see any difference in accuracy or velocity over a Magnatec II Chrono. I keep the batches of cartridges separate of course, but I could not see any difference on the targets.
The article was inaccurate. The DuPont Corporation owned and produced MR (Military Rifle) and the later IMR (Improved Military Rifle) propellants throughout the last century and alongside the Olin Corporation (Winchester) provided most US Military smallarms propellants during two world wars. It started life as a gunpowder mill in 1804 and became a major developer / producer of explosives and propellants as well as branching out into becoming one of the world's largest chemical and manufacturing companies that developed synthetic materials such as Lycra amongst other achievements.
IMR powders made until around 2003 would have 'DuPont' on the label, but at some earlier point or other, manufacture stopped in the USA and was carried out in a WW2 era plant in Canada. Early in this century, DuPont undertook a widescale divestment process and sold many of its divisions off including the IMR factory and name, it being bought by Hodgdon Powder Co. who have kept it in operation and developed new products to add to the traditional 'heritage' IMR powders.
Hodgdon brand extruded powders are made by ADI in Mulwala, New South Wales, Australia, a division of the huge Thales multinational defence conglomerate. H4350 is ADI's AR2209 which is bulk shipped to Hodgdon in Kansas where it is bottled and distributed. (Hodgdon brand ball and Hybrid powders are manufactured by St. Marks Powder, a General Dynamics owned outfit in Florida and which was formerly part of the Olin / Winchester setup.)
Hodgdon set up in business shortly after the end of WW2 and initially sold ex US government surplus powders, mostly DuPont IMR lots, some Olin manufactured ball types too. When the surplus wartime stocks ran out, Hodgdon bought the nearest equivalents to the IMR grades it could find elsewhere, initially from ICI Nobel in Scotland and when it closed from ADI in Australia. AR2208 / H4350 is similar to IMR-4350 in the sense that they have a similar burning speed and share a specific energy value of 3,760 KJ / Kg and were developed to do the same job. In fact they almost certainly have a shared history in that the Mulwala plant was built during WW2 under US supervision to manufacture IMR powders for locally produced ammunition used in the South West Pacific Theatre of Operations to avoid having to ship vast quantities of ammo and ordnance from the USA to supply its forces based in Australia.
But they are not identical today having each had 60 years of different development under different owners. In particular, the Hodgdon / ADI version has been developed with smaller grains to make it flow and meter better in powder measures and like all ADI / Hodgdon extruded powders has undergone the Extreme technology developments to make it less affected by temperature.
Not all IMR branded powders are manufactured in the Canadian facility. For its own marketing reasons, Hodgdon has named some recently introduced grades made elsewhere as 'IMR'. IMR-8208 XBR is one such as it's actually manufactured by ADI alongside the Hodgdon brand grades and is ADI's 'Bench Mark 8208' product.
Thanks for that great explanation.
Its easy to see why the confusion persists from that.
I can't find any difference in performance in my 6.5 Creedmore, but I'll put a few grains of each under a magnifier to see if I notice any difference in the grains as you mention.
Did you happen to work for them at one time? That's some pretty detailed knowledge regarding their business history.
Its easy to see why the confusion persists from that.
I can't find any difference in performance in my 6.5 Creedmore, but I'll put a few grains of each under a magnifier to see if I notice any difference in the grains as you mention.
Did you happen to work for them at one time? That's some pretty detailed knowledge regarding their business history.
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