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  #11  
Old 05-28-2017, 02:31 AM
GrocMax GrocMax is offline
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LT32 has ALWAYS been in the H322 area, thus the name, its the modern reproduction of the old benchrest surplus powder known as Thunderbird or T32, which was quicker than H322.
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  #12  
Old 05-28-2017, 04:55 AM
coyotezapper coyotezapper is offline
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With velocities that WP show in their load guide this makes more sense.
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  #13  
Old 05-28-2017, 05:02 PM
Dean2 Dean2 is offline
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Quote:
Originally Posted by GrocMax View Post
LT32 has ALWAYS been in the H322 area, thus the name, its the modern reproduction of the old benchrest surplus powder known as Thunderbird or T32, which was quicker than H322.

Not to be argumentative but the truth is actually a little different. Lt-32 and LT 322 were three batches of surplus powder sold off to the public. It was surplus 5.56 powder (Dupont 8208). LT-32 is the same as the 8208 made by DuPont for loading military 5.56. As it turns out, the batches have a faster burn rate than the newer IMR 8208 XBR.


Article you may find interesting.

Review Of IMR 8208 XBR-Hogdon's New Benchrest Powder
By James Mock
©Copyright 2009, Precision Shooting Magazine

Thunderbird T-322 or T-32 has been a favorite powder of top Benchrest shooters since first packaged in the ‘70’s. This was a military surplus powder (Dupont 8208) that was first used by Walt Berger for Benchrest shooting.

Review Of IMR 8208 XBR-Hogdon's New Benchrest Powder

Walt was contacted by the folks at Thunderbird Cartridge Company to see if the 8208 that they bought had any application for Benchrest shooting. There were three lots of this surplus powder, and Walt found one to be better than the other two. He got a second opinion from Don Geraci. Both agreed that this one lot had the characteristics for which BR shooters were looking.

Thunderbird packaged this one lot as T-322, which was soon changed to T-32 because of a conflict with H-322 and GI-322. There was some 21,000 pounds of this special lot.

The other two lots were sold as Thunderbird 8208 and many found these lots to also be very good for BR use.

Thirty-plus years have passed since the introduction of this superb powder and it has become very scarce. Most of today’s supply of Dupont 8208 comes from pull down of 5.56mm military rounds. I guess that this is better than not having any, but it leaves a lot to be desired.

A New Supply
As the supply dried up, several in the Benchrest community contacted Hodgdon to see if they would produce an equivalent powder to this early 8208.

Review Of IMR 8208 XBR-Hogdon's New Benchrest Powder

I am not sure how many approached Hodgdon with this idea, but I believe that Jerry Sharrett of Tennessee was one of the first. Hodgdon was hesitant to introduce a new powder that had a burning rate similar to some of their current offerings.

About two years ago, Lou Murdica again approached Hodgdon and they agreed to make a limited run of a powder similar to T-32. At first they said that they would produce a one-time run of 20,000 pounds.

After being well received by Benchrest shooters, and interest by the military, Hodgdon decided to add a new powder to their line of fine rifle powders.

This powder is NOT T-32, but it has properties that many will find to be exactly right for Benchrest shooting. It is packaged in a very attractive container. (Photo #1 shows a 1 lb. container.)

This powder has small extruded granules similar to the original T-32. It is light gray in color and seems to have a slower burning rate than either T-32 or N 133. It meters through my Jerry Hensler powder measure like a dream, and I don’t foresee any problem getting +/- 0.1 grain accuracy.

This new IMR 8208 XBR is made in Australia for Hodgdon and should be available by January 2010. I am betting that there will be great demand for this new powder.

Testing
I have heard that Jim Carmichel and Lou Murdica have been testing this powder with great results.

Today is October 23rd, and I have had a couple of test sessions with the new powder.
The instrument used for all of my testing is a Model B BAT-actioned /Leonard-stocked rifle with a .308 bolt face. (See Photo #2). I use this platform for both short range Benchrest as well as 600 yard competition. In the former I use a 6 PPC, and in the latter, a 6mm Dasher or 6XC. It is topped with a 36X BRD Leupold that has had its internal adjustments “frozen” by Jackie Schmidt and rests in Gene Bukys’ adjustable mounts.
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  #14  
Old 05-28-2017, 06:58 PM
GrocMax GrocMax is offline
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Same benchrest people were involved with testing the Accurate LT-32 and LT-30. After testing the 'new' Canadian IMR 8208 (graphite coated), the commercial IMR8208XBR product was sourced from ADI (gold/yellow/tan color) and ended up being too slow for 6PPC, so they started all over with Accurate on trying to reproduce that magical mythical lot of too fast surplus 8208 everyone 6PPC loved so much. Its gone full circle again, now they complain about the new LT-32 slowing down, so they mix LT-32 and LT-30 and call it LT-31. They complain about N133 slowing down too compared to the 'good old days'.
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  #15  
Old 05-29-2017, 01:20 AM
coyotezapper coyotezapper is offline
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Here is a burn rate chart I got from TCCI back in 2002. I don't remember why they had IMR8208 under their brand.
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  #16  
Old 05-30-2017, 02:34 AM
GrocMax GrocMax is offline
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Was getting some 223AI fireform and full loads worked out today, had some time to mess around a bit. 50TNT and same OAL, have a jug of milsurp pulldown IMR8208 from the last batch that got demilled in 09/10. In a direct comparison to current IMR8208XBR ADI mfg powder, the old pulldown milsurp is quite a bit faster, a tick quicker than current H322 and a tick slower than current AA2015 with the above components. The current ADI IMR8208XBR is very close to, maybe slightly slower than current Benchmark with the above components.

Obviously case size and bullet weight will change things, but that's what I saw today with 50g Speer TNT 223AI full loads with ADI made IMR8208XBR, Benchmark, H322, AA2015, and 09/10 vintage pulldown IMR8208. I'd call the pulldown 8208 very close to 2015 in both bulk density and speed, and they are made at the same facility in Canada.

I was gonna try LT-32 but couldn't find the jug. Its close to N133 in speed and bulk density in the 223AI.

Last edited by GrocMax; 05-30-2017 at 04:36 AM.
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  #17  
Old 06-01-2017, 05:36 PM
coyotezapper coyotezapper is offline
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Went back out to the range yesterday and was able to chronograph charges I wanted to test further. All tests were two, five shot groups of each charge with the Oehler chronograph set ten feet in front of muzzle. Here are the results.

17 grains averaged 3530 fps
17.1 grains averaged 3554 fps
17.2 grains averaged 3575 fps
Powder seems to be very linear.

This is very close to WP load data on their website so I think that the burn rate for this powder is right where they have it on their chart.

Accuracy was .4" - .6" for all groups with only one being in the .6's. I may play with seating depth but have not decided yet. The accuracy I am seeing right now should hold pretty well out to 400 yards for PD's and RC's.

ES was a lot higher than I liked, 54-70 fps so when I got home I weighed each case and compared it to the actual velocity for each case and it was clear that the case capacity for each round fired was the culprit. Heavier cases had higher velocities and lighter had lower. I plan to try a couple of different primers and weight sort cases with next test to see if I can't get the ES down. The testing so far has been with the original sixty pieces of brass I got with the rifle and I never had to sort by weight before with other powder and bullets so I think sorting them into half grain lots should help.

I am still thinking this powder is a good choice for this cartridge.
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  #18  
Old 08-07-2017, 04:11 PM
coyotezapper coyotezapper is offline
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Just thought I would update latest testing with this combo.

I was never able to solve the high ES issues. Sorting brass by case capacity made no difference and neither did primer change. I thought the case capacity differences was the culprit at first but weight sorting showed no difference. Original data point turned out to be wrong and confirmed original load results which showed no need for weight sorting. I can only think of one other time where primer change has not had some effect on ES but in this case it had none. Now by none I mean that the ES issues did not go away. Each primer showed different velocities but they still had high ES's.

All of this testing was done with naked bullets. I decided to go ahead and hBn coat these bullets and repeat the tests but the results were still the same. With my 17's I develop loads first with naked bullets and then hBn coat them and then increase powder charge weight to match naked bullet velocities for final load.

Now being that my original bullet / powder combo's worked so well I attribute these issues to this powder. Just not a good match. QL does not show LT32 in its library of powders so all of this was just hoping it would work with no other data points to rely on. I have decided to move on to IMR4198 and N540 as QL shows them both to be the ideal powder bullet combo.

Last edited by coyotezapper; 08-07-2017 at 04:23 PM. Reason: spelling
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  #19  
Old 08-07-2017, 04:58 PM
Dean2 Dean2 is offline
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Quote:
Originally Posted by coyotezapper View Post
Just thought I would update latest testing with this combo.

I was never able to solve the high ES issues. Sorting brass by case capacity made no difference and neither did primer change. I thought the case capacity differences was the culprit at first but weight sorting showed no difference. Original data point turned out to be wrong and confirmed original load results which showed no need for weight sorting. I can only think of one other time where primer change has not had some effect on ES but in this case it had none. Now by none I mean that the ES issues did not go away. Each primer showed different velocities but they still had high ES's.

All of this testing was done with naked bullets. I decided to go ahead and hBn coat these bullets and repeat the tests but the results were still the same. With my 17's I develop loads first with naked bullets and then hBn coat them and then increase powder charge weight to match naked bullet velocities for final load.

Now being that my original bullet / powder combo's worked so well I attribute these issues to this powder. Just not a good match. QL does not show LT32 in its library of powders so all of this was just hoping it would work with no other data points to rely on. I have decided to move on to IMR4198 and N540 as QL shows them both to be the ideal powder bullet combo.
If it is all about just having fun then continue on, it also makes good reading so keep filing updates. If you want really good groups with max velocity, and very low ES on 20 and 25 grain bullets, just try Benchmark instead of messing around. 25 grain Vmax out of a 26 inch Rem factory barrel ES 29 Benchmark 18.8 grains, CCI SR primer delivers 3877 fps and .20 groups.
If you want low ES and very good accuracy/velocity with 30 grain bullets, either Benchmark or 8208 will give you great results.

I have tried just about every suitable powder in a number of different 17 FBs and that is what the testing showed me.
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  #20  
Old 08-08-2017, 03:43 AM
coyotezapper coyotezapper is offline
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I try to stay with powders that QL recommends as best fit. I have looked at Benchmark a couple of times because of all the good reports on it but have shied away from it because QL only shows it as just ok. The only reason I tried LT32 is because I have an 8 lb. jug sitting on the shelf.

I did the 30 grain bullet - Kindler Gold with RL10X and 8208 with good results but wanted a cheaper bullet for some of my high round count dog towns. I am of the opinion that the 25 grain bullet is ideal for the 17FB case.

I have both IMR4198 and N540 on the shelf so I am hoping one of these is the answer.

Last edited by coyotezapper; 08-08-2017 at 03:48 AM. Reason: add
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