MontanaRifleman
Well-Known Member
....
H1000
- Thread starter Mabia
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It looks like I picked up 45 to 50 fps with the new lot of powder. The Magneto Speed is a useful piece of equipment, I don't know why I didn't get one sooner.
I plan to stay with H1000 until powder becomes more readily available.
I plan to stay with H1000 until powder becomes more readily available.
Most of the time, I feel unworthy to udder a sound around such paragons of wisdom- but I do have a big mouth and an additude
I know not of your MV variations, but when I read that you were using a Magneto Speed to record your velocities, a bell knocked me off the couch. I use a MS pretty exclusively now until I can get my CED M2 working like its supposed to. What I have noticed is that my POI moves 1-2 moa north when I strap the MS on. Just a guess- the MS effects barrel harmonics. Not to worry though- All the groups on all my Bolt Guns and Battle Guns are repeatable strapped on vs. off. I shoot for groups w/ the MS strapped on, and zero with it off. I will not zero w/ MS attached. I have not used the MS for OCW studies or laddering, but intend to very shortly. After I've shot for OCW and/or laddering with MS attached, I'll confirm with it off- hope it works..
As a wise old Bear once told me, " Measure twice, cut once!"
Note- My McMillan TAC 300win mag w/22in bbl eats that H1000 like it's candy- 74.5gr's behind a 208gr. Amax @2830fps- 3.43OAL (depending on meplates) I'm interested to see how the H1000 works in a McM-338LM- this one still has the 26" barrel.
Carry On-
Mike
About two years ago I experienced similar velocity changes from different lots of Retumbo. At the same time, a buddy of mine experienced the same kind if change with H1000. The change with Retumbo seemed to occur about 2 years ago with a new lot producing a 50-60 FPS increase, requiring a decrease of 1.5 gr to 57.5 in my 6.5x284 to get the same velocity of 2970FPS. There was no pressure signs with the new lot using the higher charge but my accuracy peak was the same between the two lots at 2970 FPS. It seemed like a change took place with one of the base formulations that Hogdon uses in their powders. Since then, a few more different lots of Retumbo produced the same results using 57.5 gr. I have had a few buddies with 6.5x284's and a few shooters on this site that purchased Retumbo over the last year or so and generated similiar velocities using the same charge weights. I haven't had any experience with different lots of H1000 since I'm still working on a large supply that I've had for a while, but so far it looks like Retumbo has been pretty consistent since the last change a couple of years ago. I've settled on Retumbo in my 6.5 and 300's mostly because it generates about 2-3% higher velocity at similar pressures than H1000, but also because from my experiences it does appear to have been pretty consistent over the last couple of years.
D.Camilleri
Well-Known Member
I first tried H-1000 in my 338 RUM years back and it wouldn't give me the velocity I was after because it was too slow burning. Then several years ago, something changed and now the burn rate is perfect. I still have one pound of an old batch left that I won't use at this time. When I bought my last batch, I bit the bullet and bought 8 pounds. I have run into similar problems with RL 22 and I quit using it, because it acted just like RL 19. The old lot of H-1000, I used to be able to load 102 grs with a 225 accubond and get about 3150 fps, with the new lots I can load 97 grs and get 3300.
After extensive testing I discovered my jump in velocity was a combination of of two things, new brass and the powder lot change. I still have 25 to 30 fps with the new lot of H1000. Once fired brass seems to settle about 2800 fps where new brass shoots 2840 fps. My original load worked out to 2750 fps using Bergers Ballistic program to calculate drops.
All of my testing was done using Remington Brass, I plan to do some testing with new and once fired Bertram brass.
Randy
All of my testing was done using Remington Brass, I plan to do some testing with new and once fired Bertram brass.
Randy
I have been forming 7mag brass with h1000 all week. Velocity jumped 100fps from gm210m to cci250 verified by two chronos back to back then reversed.
I would expect new brass to expend a lot of the powders energy to expand. Meaning new brass velocity would be slower. However new win. brass 72gr h1000 cci250 168vldh was 3020/3024fps 24 in bbl. Thats pretty fast for that load.
Do you always see lower speed same load on once fired brass?
I would expect new brass to expend a lot of the powders energy to expand. Meaning new brass velocity would be slower. However new win. brass 72gr h1000 cci250 168vldh was 3020/3024fps 24 in bbl. Thats pretty fast for that load.
Do you always see lower speed same load on once fired brass?
My experience with fired vs new brass and the effects on velocity is dependent on the rifle's chamber. I measure the case capacity between the two. If the capacity changes, the velocity can as well, all other as parameters of the load reminding constant. Generally, larger case capacity results in lower velocity under this circumstance. I have also found Winchester brass to be thinner in wall thickness which can pronounce the chamber/case capacity effects.
I check outside dimensions in 4 places and headspace datum points on the shoulder all my brass between 1st and 2nd firings. Shoulders expand .018 to .020 on headspace and up to .005 diameter first fire form on belted cases.
That's a lot of expansion compared to non belted cases.
Since my last post I checked my notes from 1st to 2nd brass firing with the same load on my factory chamber 7mag Sendero I was surprised that the velocities were within 5-10 fps depending on the SD of the group. AND the temp. was 20 degrees difference and using Imr4350!
Only difference in in groups was once fired brass had less obvious fliers and maybe .01 tighter groups
That's a lot of expansion compared to non belted cases.
Since my last post I checked my notes from 1st to 2nd brass firing with the same load on my factory chamber 7mag Sendero I was surprised that the velocities were within 5-10 fps depending on the SD of the group. AND the temp. was 20 degrees difference and using Imr4350!
Only difference in in groups was once fired brass had less obvious fliers and maybe .01 tighter groups
