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Old November 4, 2012, 09:29 PM   #1
twobit
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4320 powder question

I've found my late father's reloading notes and have a question?....
In 1976 He loaded a great round for my bolt action .270 and refers to the powder being 4320 but does not list the brand. Here is the recipe....
48 1/2 grains of 4320 for a 130 grain Norma soft point boat-tail (nickel colored bullet). Primer was 210 Federal. His notes say "about 3000 fps".

When I look up 4320 in modern data it states never exceed 47 grains. My father would have never exceeded posted limits on anything he reloaded. If the 4320 he used was the same as i find today then he exceeded the maximum by 1 1/2 grains per today's charts! My question is ...is the current IMR 4320 the same powder that he used in 1976?

I still have and still shoot some of those 1976 reloads in the same gun. It is an excellent whitetail round. I would like to recreate that same load today although I don't think I could find the Norma bullet he used. Please help me determine if the powder is the same...thanks
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Old November 4, 2012, 09:36 PM   #2
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Max powder charges sometimes get reduced for lot to lot consistency reasons, or known issues with some firearms.

The only way to do a safe load workup is to start at the starting charge and work your way up looking for pressure signs. IMR powders are generally very consistent lot to lot, but I wouldn't bet on the variation over 3 decades.

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Old November 4, 2012, 10:00 PM   #3
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Good advice..thanks.
A further question...was 4320 a IMR product in 1976 or did another company have a powder named 4320? I was a teen then, and I think most of his old powder cans said DUPONT. Did DuPont become IMR?
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Old November 4, 2012, 10:30 PM   #4
Mike Irwin
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IMR is not a company. It is a product line.

In 1976 Du Pont was manufacturing IMR powders, as they had been since the 1920s, or when IMR (Improved Military Rifle) powders replaced the then standard MR (military rifle) powders.

Powder lots and formulations change over time, as do sensibilities on what is, isn't, and should be safe loads.

In 1976, measuring chamber pressures was also QUITE a bit different. It was done with copper crushers, and was, in large part, and art of guesstimation.

Now days pizoelectric transducers and strain gauges are FAR more reflective of actual chamber pressures, and far more repeatable.
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Old November 4, 2012, 11:01 PM   #5
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CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

Something is odd with that data..

Hodgdon's website lists 47.0gr 4320 as max load under a 130gr bullet and it's listed in CUP, which usually means that it's not really "recent" data. Anything they've tested recently is listed in PSI.

If I plug the info into QuickLoad, it thinks that both of those loads are FAR from max pressure. It's so much higher that I triple checked the settings to make sure I wasn't putting in the wrong powder or something.

According to QuickLoad, 48.5gr would be close to a STARTING load, with both Hodgdon/IMRs Hornady SP bullet and the Norma bullet listed by the OP and if I put in 47.0gr Hodgdon max, the predicted velocity is only off Hodgdon's speed by 34fps. The predicted pressure of a 47.0gr load is only 50,313psi, max is 65,000.
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Old November 4, 2012, 11:02 PM   #6
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Keep your dad's notes in a special place at your reloading bench.

Work up a new load for yourself. IMR4320 is a good powder and I've burnt a lot of it, but for every rifle I have I've found something else that works better. I don't have a .270 so YMMV.
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Old November 5, 2012, 08:00 AM   #7
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As I have noted here in the past, the IMR powders are probably the most forgiving powders available.

They can provide exceptional accuracy with with loads that vary by as much as a grain in absolute weight.
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Old November 5, 2012, 09:36 AM   #8
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Thanks to all replies.

I have found Papa's hand written data both in his reloading notes ( a small spiral notebook) and in each remaining loaded box of that ammo on a label he put in each box. The data he wrote down for that load is all identical in each place it is written, so I know it is not a mistake on his part in writing it down. He just never wrote the "brand" of the powder down anywhere, just "4320". Unfortunately I have none of his old powder cans. From everyone's replies I feel more confident that he was indeed referring to IMR powder.

Out of about six original boxes of that recipe, that he loaded in 1976, I still have about two and a half twenty round boxes remaining. He died in 1985. This was the last recipe he ever loaded for me for the .270. I helped him load it. We both quit reloading in about 1978. I started back up about five years ago.

I still use this ammo sparingly at the rate of "one round = one deer." I may have enough to last my lifetime at that rate, since I'm 52. That recipe was the last of several different recipe's Papa worked up for me and my rifle over a four year period and it is by far the best I have shot for whitetail at 80 to 200 yards. I shoot it out of a custom .270 he made for me using a Shilen barrel / Santa Barbara Mauser action. He bought a walnut stock blank and did all the stock work himself including hand checkering. It was my Christmas present in 1972. I only shoot those rounds in that gun.

The recipe is so good that a shoulder shot to the optimum whitetail target zone always seems to go all the way across the lung area and stop near the skin on the far side, using up all it's energy in the process and leaving a perfect mushroomed bullet. The deer usually drop in their tracks. To me that is a great recipe.

The best part is that each shot brings up the strong happy memories of hunting with Papa when I was a teen.

Oh.... I sat in my blind two days ago on opening morning and watched three does for a couple of hours. Yes I had that rifle with one of those rounds in the chamber. I did not shoot at anything. The season is long, and I live on the ranch, so I have many opportunities to bag just the right deer for the freezer. Mainly I sat there and thought of past hunts with Papa.
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Old November 5, 2012, 09:55 AM   #9
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IMR 4320 pressure will vary from lot to lot. If you plan on using this powder I would consider buying the 8# jug.
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Old November 5, 2012, 10:06 AM   #10
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Man, I never thought talking reloading would put a lump in my throat. That's a great story. What gun to cherish! I'd save at least one of those rounds too, should you find yourself shooting more deer than you might imagine.
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Old November 5, 2012, 11:57 AM   #11
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Oh yes I'll save sample rounds of every recipe that Papa reloaded and I plan on putting the little recipe book and some of those rounds in a shadow box someday.
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Old November 5, 2012, 10:07 PM   #12
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As with all loads, start low and work up. IMR powders are what used to be DuPont; the newer data books have all been lawyerized as in reduced charges to preclude lawsuits. 4320 is one of my stalwarts in reloading; I've even used cans that had red dust puffing out when poured into the measure! I did what the man that taught me to reload did and gently blew the dust away while pouring it slowly into the hopper! It works extremely well in the 30/06, 270 with light bullets, and is the time honored powder of choice in the 22-250 and 222 Rem Mag.
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Old November 5, 2012, 10:17 PM   #13
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"IMR powders are what used to be DuPont"

Actually, IMR powders were manufactured BY Du Pont.

IMR actually denotes powders that were coated with a burn restrictor and graphite.

The first ones were developed right around World War I.
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Old November 6, 2012, 08:51 AM   #14
twobit
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Yes I will start low and work up when I get some new 4320. I have found a similar bullet to the old nickel colored Norma soft tip boat tailed 130 grain that Papa used in the old loads. It is a Speer #1458 soft tip boat tailed with a copper colored jacket. Hopefully it will have the same expansion characteristics as the old Norma.

Thanks to all that responded to this thread.
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Old November 6, 2012, 09:33 PM   #15
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The Norma bullets are pretty tough. I've used 4320 in my .338-06 since 1988. As mentioned, it's a very forgiving powder. You might consider using a slower powder like RL-19 or IMR 4831 with Hornady Interbonds or GMX bullets.

That was a really great story about your Father and it's great to hear that some still honor their fathers.
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Old November 9, 2012, 05:29 PM   #16
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What a memory, you are one lucky man to have had a father like him. William
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Old November 9, 2012, 08:29 PM   #17
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twobit, There was nothing wrong with your Dad's reloads. I started loading later part of 1965 and Lyman manual #45 published 1970 they list start load for the 130gr bullet for the 270 @ 44gr/IMR-4320 and max load of 50.5gr/IMR-4320.

They did change individual granule dia and length for IMR-4320 not listed what year that was done. About 15yr maybe little longer they were going to stop making IMR-4320 it was the powder for the 17 Rem at that time anyway they must of gotten lot of complains as they decide to keep making it.

I think Hodgdon may be the only manual that list IMR-4320 for the 270 with 130gr bullets.

Well good luck
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Old November 10, 2012, 09:08 PM   #18
twobit
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Thanks Old Roper. Are you saying that the old 4320 formula is different from what they make now and that is why the new data is different from the old Lyman data? I may have an old Lyman manual, I'll have to look in some old boxes.
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Old November 10, 2012, 09:22 PM   #19
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That's what they're saying. If you have the old powder and it hasn't deteriorated you can use the old data. I'd use current data with any new powder.

I don't think he was trying to make a magnum out of your .270 and neither should you. Find the sweet spot for accuracy and you will have a very effective game getter. Those last fps only make a difference when looking at a chronograph display. The targets really don't care.
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Old November 10, 2012, 09:28 PM   #20
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Update

Just found two of Papa's old Lyman reloading manuals.
One is dated 1953. One is dated 1957. I wasn't born until 1960. Wow, such neat books! .....And yes they show the data that Old roper referred too.
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Old November 10, 2012, 09:30 PM   #21
twobit
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No I don't have any of the old powder so if I use new 4320 powder it will be with new data only.
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Old November 11, 2012, 05:52 PM   #22
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twobit,
A very interesting post. You have some history in your rifle and loads, which many of us envy.

I dug out some of my old loading notes from 1975 and for the .270, I used mainly Dupont IMR 4064. There is one entry using 50.5 grains of IMR 4320 behind a 130 grain Sierra SPBT and it was quite accurate. My Du Pont list from that era lists a load of 45.5 grains behind a 130 grain Nosler Partition bullet. The Speer manual, 1974 printing, does not list any .270 loads with IMR 4320. However, the Hornady manual, 1973 printing, list a maximum load of 52.5 grains of IMR 4320 behind a 130 grain SP bullet. As powders can vary over time, I would look for newer data before loading. Having said all this, I was always prudent and started with low loads and worked up.
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