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Are 4350 powders interchangable?
- Thread starter USAF Ret
- Start date
Like bullets of same weight but of different designs, they are not the same but similar. Close enough won't cut it for loading ammunitions, especially when it is close to max charges.
Happy new year. May safety and good accuracy be with you all. God bless!
-TL
Sent from my SM-N960U using Tapatalk
Happy new year. May safety and good accuracy be with you all. God bless!
-TL
Sent from my SM-N960U using Tapatalk
Point of interest: I have 2 cans of IMR-4831 from a deceased fiend's inventory (age??) but I have always used H-4831 max load of 56.0gr in my .270 with a 150gr Hornady Spire.
Given the cost, etc. of components today I decided to use up the IMR-4831.
Hodgdon's 27th Ed (date??) lists H4831 max as 55.7gr (2804fps) 51,200 CUP and IMR4831 55.0gr (2920fps) 51,400 CUP.
But the 50th Ed of Lyman's manual lists max loads H4831 at 56.0gr (2788fps) 51,200CUP and IMR4831 54.3gr (2860fps) 52,000CUP.
As AMP has commonly advised, what THEY obtain in THEIR rifles may not be what I will get in mine. But since I have a long track record using 56.0gr of H4831, I'm comfortable starting the IMR loads with 54.0gr. I'm not as interested in the velocity as I am in accuracy, so I won't chronograph them to compare to the manuals. But I will watch pressure signs with the IMR as it seems to produce higher pressure with less powder, very evident in the newer Lyman manual.
Given the cost, etc. of components today I decided to use up the IMR-4831.
Hodgdon's 27th Ed (date??) lists H4831 max as 55.7gr (2804fps) 51,200 CUP and IMR4831 55.0gr (2920fps) 51,400 CUP.
But the 50th Ed of Lyman's manual lists max loads H4831 at 56.0gr (2788fps) 51,200CUP and IMR4831 54.3gr (2860fps) 52,000CUP.
As AMP has commonly advised, what THEY obtain in THEIR rifles may not be what I will get in mine. But since I have a long track record using 56.0gr of H4831, I'm comfortable starting the IMR loads with 54.0gr. I'm not as interested in the velocity as I am in accuracy, so I won't chronograph them to compare to the manuals. But I will watch pressure signs with the IMR as it seems to produce higher pressure with less powder, very evident in the newer Lyman manual.
reynolds357
New member
No, they are not.Are Accurate 4350, H4350, and IMR4350 interchangeable for load data?
A caveat to this is that I have seen as much deviation in lott number as I have seen between brands.
Are Accurate 4350, H4350, and IMR4350 interchangeable for load data?
Ask the manufacturers. Whenever you have a question about a product, ask the manufacturer. Forums are not a good place to get facts.
CAUTION: The following post (or a page linked to) includes or discusses loading data not covered by currently published sources of tested data for this cartridge (QuickLOAD or Gordon's Reloading Tool data is not professionally tested). USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from the use of this information.
Cdoc42,
According to Amazon, Hodgdon's 27th is from January 1998. Hodgdon did not purchase IMR until October 2003. This means the Hodgdon load data for IMR powder back in 1998 would have been developed with an off-the-shelf lot of the powder whose exact burn rate may or may not have been typical. IIRC, the burn rate of IMR powders was held to ±5% then, and Hodgdon has upgraded their QC since then.
The use of off-the-shelf powder is one of the reasons different load manuals have different minimum and maximum loads. Hodgdon will be the current keeper of the actual powder specifications and powder data lots, so their data will be closer than anyone else's for powder bought after 2003, and is probably the most reliable data. They say H4831's maximum 150-grain bullet load is 5.1% heavier than the maximum load for the IMR product. The minimum charge weight for IMR 4831 will product about 3% less pressure if current H4831 is substituted, but the maximum charge weight for H4831 produces over 8% higher pressure than the same charge weight of the IMR product. This means the IMR product raises pressure faster with increase in charge than the Hodgdon product does, so there won't be a constant ratio of the two that works. That ratio will vary with the peak pressure.
My logarithmic curve fit software, using the Hodgdon data for both powders with a 150 grain bullet, say that, in a 24" barrel 53.4 grains of current production IMR 4831 will match the peak pressure of current production H4831, and 53.0 grains (the current max from Hodgdon for the IMR version) will match your H4831 load's velocity. However, this assumes you have Hodgdon's lots of powder, and you don't. Given the 5% burn rate tolerance from the old days, it could take as little as 51.7 grains of the IMR product to match velocity.
Then we have the issue of the powder age. If its relative burn rate had declined with age, no problem. If if has suffered the pressure increase scenario, it could be a problem, and for that reason, I recommend you actually make seven rounds with 46.3, 47.4, 48.4, 49.5, 50.5, 51.6, 52.7 grains to fire in that order as a double-check for pressure signs, then make sure you haven't exceeded your H4831 load's velocity.
Cdoc42,
According to Amazon, Hodgdon's 27th is from January 1998. Hodgdon did not purchase IMR until October 2003. This means the Hodgdon load data for IMR powder back in 1998 would have been developed with an off-the-shelf lot of the powder whose exact burn rate may or may not have been typical. IIRC, the burn rate of IMR powders was held to ±5% then, and Hodgdon has upgraded their QC since then.
The use of off-the-shelf powder is one of the reasons different load manuals have different minimum and maximum loads. Hodgdon will be the current keeper of the actual powder specifications and powder data lots, so their data will be closer than anyone else's for powder bought after 2003, and is probably the most reliable data. They say H4831's maximum 150-grain bullet load is 5.1% heavier than the maximum load for the IMR product. The minimum charge weight for IMR 4831 will product about 3% less pressure if current H4831 is substituted, but the maximum charge weight for H4831 produces over 8% higher pressure than the same charge weight of the IMR product. This means the IMR product raises pressure faster with increase in charge than the Hodgdon product does, so there won't be a constant ratio of the two that works. That ratio will vary with the peak pressure.
My logarithmic curve fit software, using the Hodgdon data for both powders with a 150 grain bullet, say that, in a 24" barrel 53.4 grains of current production IMR 4831 will match the peak pressure of current production H4831, and 53.0 grains (the current max from Hodgdon for the IMR version) will match your H4831 load's velocity. However, this assumes you have Hodgdon's lots of powder, and you don't. Given the 5% burn rate tolerance from the old days, it could take as little as 51.7 grains of the IMR product to match velocity.
Then we have the issue of the powder age. If its relative burn rate had declined with age, no problem. If if has suffered the pressure increase scenario, it could be a problem, and for that reason, I recommend you actually make seven rounds with 46.3, 47.4, 48.4, 49.5, 50.5, 51.6, 52.7 grains to fire in that order as a double-check for pressure signs, then make sure you haven't exceeded your H4831 load's velocity.