Question regarding IMR 4320

[coorslight]

I recently came across some IMR 4320, I have been using 30.0 gr. Varget with 108 Bergers, read a bunch of posts about it being the same as Varget but not a lot of suggestions for loads. Can I use about the same charge of 30 gr or should it be backed off a bit or increased to get the same results. Components are getting scarce so don't want to do a lot of testing, Have enough to finish off the season in competition. Thanks in advance

 

[Big Mc]

I recently came across some IMR 4320, I have been using 30.0 gr. Varget with 108 Bergers, read a bunch of posts about it being the same as Varget but not a lot of suggestions for loads. Can I use about the same charge of 30 gr or should it be backed off a bit or increased to get the same results. Components are getting scarce so don't want to do a lot of testing, Have enough to finish off the season in competition. Thanks in advance

With any powder change Start low work up. Just my two cents Tommy Mc

 

[watercam]

Hodgdon Reloading.com alloas one to compare Varget vs 4320 side by side online

 

[0.1 Aggregate]

I recently came across some IMR 4320, I have been using 30.0 gr. Varget with 108 Bergers, read a bunch of posts about it being the same as Varget but not a lot of suggestions for loads. Can I use about the same charge of 30 gr or should it be backed off a bit or increased to get the same results. Components are getting scarce so don't want to do a lot of testing, Have enough to finish off the season in competition. Thanks in advance

How can we possibly give you relevant feedback without knowing the cartridge you will be stuffing the 4320 into?

 

[coorslight]

How can we possibly give you relevant feedback without knowing the cartridge you will be stuffing the 4320 into?

I can't believe I forgot to list the cartridge, 6 BR Norma, It's tough to get old. My apologies.

 

[coorslight]

Update loaded up some Berger 108's yesterday and tried them at 200 yards 29.0 and 29.5gr both grouped well with the 29.5 grain a bit better but was surprised that it pierced a couple of primers. I'll try 29.2 at 600yds on Thursday

 

[Ned Ludd]

FWIW - IMR4320 has been discontinued for a while. If you like it and have a source to get some more, better buy some extra while you still can as it will likely be unobtanium in the future.

Several years ago, I did some load development for a .308 Win with 185 Juggernauts side-by-side with Varget. The velocities obtained with IMR4320 were almost identical to those generated by Varget on a charge weight basis. However, the IMR4320 seemed much more sensitive to pressure, quite abruptly blowing a couple primers toward the upper end of the charge weight test, even though the highest charge was still under predicted MAX. In contrast, I think I could have gone at least a couple charge weight increments higher with Varget as it did not show the same pressure signs, even though the velocity was comparable. For that reason, my feeling is that the IMR4320 should work just fine in your situation, but I would try not to pick a node that is very close to MAX. If you start low and work up incrementally, you ought to find a node somewhere in the middle of the suggested charge weight range that will work, but won't be so close to the high end where IMR4320 might rather abruptly and/or unexpectedly show pressure signs.

 

[coorslight]

FWIW - IMR4320 has been discontinued for a while. If you like it and have a source to get some more, better buy some extra while you still can as it will likely be unobtanium in the future.

Several years ago, I did some load development for a .308 Win with 185 Juggernauts side-by-side with Varget. The velocities obtained with IMR4320 were almost identical to those generated by Varget on a charge weight basis. However, the IMR4320 seemed much more sensitive to pressure, quite abruptly blowing a couple primers toward the upper end of the charge weight test, even though the highest charge was still under predicted MAX. In contrast, I think I could have gone at least a couple charge weight increments higher with Varget as it did not show the same pressure signs, even though the velocity was comparable. For that reason, my feeling is that the IMR4320 should work just fine in your situation, but I would try not to pick a node that is very close to MAX. If you start low and work up incrementally, you ought to find a node somewhere in the middle of the suggested charge weight range that will work, but won't be so close to the high end where IMR4320 might rather abruptly and/or unexpectedly show pressure signs.

Thank You, I know it has been discontinued, my friend that I shoot with owns a gun shop and had 3 pounds of it, bought a pound to experiment with, if it works out to be a good substitute for Varget ill use it until Varget is more available, he is holding the other 2 pounds for me. Thanks for your input

 

[Hudge76]

While 4320 has been discontinued, 2 of my LGS have gotten shipments of it since April. They each got a couple of cases of 1lb containers. You know a stash must have been found as they all had red metal lids on it while all others on the shipment had black plastic lids.