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Post by sew on Nov 29, 2021 11:05:30 GMT -5
I rechecked my sighting in of my Ultralite Jimbob 40 yesterday evening. As usual, I was in a cutover agricultural field shooting off of a stable foldup table, Hart adj rest, #13 rear bag. Very light wind. 2x8 scope on “8x” .
Still, no load work up. 228g AM, 62g H322, DI, Win LRMPs, WW (needed?), 2770-2780’/sec.
In Jan, I’ll start on serious load development on both JB 40s. 99% of my shot possibilities will be well below 300 yds.
Results:
100 yds 2.4” hi, <0.5” gp (ragged hole)
200 yards 0.6” hi, 0.9” 3-shot gp
300 yards 6” low, 6” group!!
I have no idea why the 300 yd group opened up so much. 8x isn’t ideal for 300 yds but wasn’t a major factor in the large group obtained. 3-5 mph wind, predominately L->R.
Going back and reviewing the late evening shooting, the wind was becoming a little stronger and more inconsistent. Maybe 5-7 mph variable during the 300 yard shooting.
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Post by sew on Nov 29, 2021 11:09:02 GMT -5
100 yd  |
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Post by sew on Nov 29, 2021 11:22:09 GMT -5
200 yards. Ignore the 4th higher shot. That was from a much tighter bullet (sized larger).  |
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Post by sew on Nov 29, 2021 11:26:27 GMT -5
300 yards. Ignore the shot in the red. I’d forgotten to spot over it or it had fallen off. The 3 lower shots are the “group”. Suggestions solicited!  |
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Post by dennis on Nov 29, 2021 11:34:47 GMT -5
Parallax adjustable? just asking as I have similar issues up close with 100yd fixed parallax.
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Post by sew on Nov 29, 2021 12:05:51 GMT -5
It’s a 2x8 Zeiss Duralyt. I’m, by no means, a scope expert, but seriously doubt that parallex could cause this. The Zeiss Duralyt 2x8 is a mid-range scope, and I think of100-300 yards as mid-range.
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Post by joelmoney on Nov 29, 2021 21:26:17 GMT -5
Bottom left doesn’t look perfect. Bullets losing stability? What twist are you shooting? Exactly why I like shooting to find my drops instead of printing them.
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Post by sew on Nov 29, 2021 23:29:41 GMT -5
Joel,
My thoughts, which could very well be wrong, are that the bullet starting at 2770-2780 and still slightly sub-MOA @200 yards , I don’t think the bullet would become unstable by 300 yards. It should still be >2000’/sec. I think it was affected by wind and likely some of me. I’ll be back out. 14 twist.
More coming. Love this rifle!
Steve
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Post by joelmoney on Nov 30, 2021 0:57:37 GMT -5
Looked at Kyle’s twist rate tables unless your shooting 1-24” or slower that probably isn’t the answer.
On 8X how well are you able to quarter your red dot?
Do you use a scope level?
One gust certainly could have made the horizontal dispersion. I was looking at taking a shot Saturday night and after looking at what my wind hold would be decided against it and I’m shooting 325’s starting at 2970.
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Post by sew on Nov 30, 2021 8:58:58 GMT -5
Joel,
No scope level on the light rifle , but there will be today! The lighted Duralyt has tiny center xhairs, unlike the unlighted version. I don’t think xhairs/red dot was the major problem. After season is over, a 6x24 B&L 4200 with a tgt dot reticle will be used for serious load work up. Tilt certainly could have played a major factor and compounded by increasing variable winds. Thanks.
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Post by joelmoney on Nov 30, 2021 14:25:51 GMT -5
Steve
Just throwing ideas out there. Hoping to stumble on something you hadn’t thought of. Sounds like you have it covered. I wish you luck but assume you won’t need it.
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Post by sew on Nov 30, 2021 15:43:59 GMT -5
Joel,
3 scope levels coming from Optics Planet. You, not me, hit on something. Thank you. I have scope levels on my xbows but not on my rifles! 😳
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Post by hillbill on Dec 1, 2021 5:43:51 GMT -5
I would bet Steve that's at least some of the issue but it's easy to find out?
All of my guns wear a level just for that very reason, anyone that thinks they can hold their gun level at long distance without one is a better man than I, they are relatively light weigh and low profile and don't cost a lot.
Cheap insurance! it's now second nature to look at the level before a shot, especially at longer distances.
I use mainly Holland levels and mount them forward of the side focus out of the way of my fingers, it's easy to see with both eyes open on the scope.
Grouping like that at 100 and 200 I can't imagine the bullet going south at 300, might have been just one of those days?
It will be interesting to see what difference the level makes, keep us posted.
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Post by sew on Dec 1, 2021 15:03:07 GMT -5
Bill, I don’t think it was the bullet. I think some of it was me. There is a windbreak for about 225 yards (to the West which is where the wind was from) so the last 75 yards could have been affected. Of course, we both know that the earlier the wind affects a projectile, the greater effect it has.
I’m just getting started. This gun will end up shooting very well!
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Post by sew on Dec 4, 2021 23:11:03 GMT -5
Just for a re-visit of the scope levels which haven’t arrived yet.
I shot the full sized, 18# (rifle/scope) Jimbob 40 cal. 6x24 Sightron. Same table, same rests, same lack of scope level, but 24X, parallex adjust. Load was 73g H4895, (DI), 278 AM, no wad, 2870’/sec.
The wind was a little worse, ie shooting conditions were slightly worse. This was a quick check of sighting-in at 100-300 yards. I was having significant fouling problems and very uneven loading pressures - most were extremely tight - way too tight. This had to significantly hurt group size. This rifle normally cloverleafs at 200 yards and about 1” at 300 yards.
Here are the results:
100 yd (<1” gp) 2” hi
200 yd (1” gp) 3.1” hi
300 yd (1.9” gp) 4” low.
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Post by jims on Dec 5, 2021 9:34:55 GMT -5
Grouping well under those conditions.
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Post by sew on Dec 5, 2021 16:39:50 GMT -5
I have lots of questions going forward. Without question, the scope levels will help.
The following questions pertain to the larger, much more robust 40 cal Rem 700/RC barrel.
1) Two finger push down of the bullet. 1 finger and thumb, or more likely, 2 fingers on the top of the range/ram rod?
2) Using my comparatively light load of 73g H4895/278gAM (full formed 254, 4085 Hammer soon) with DI, would a duplex like 5g VV110/68-69g H4895 (more like a 76-78g H4895 load) be helpful at reducing the fouling that is occurring? I’m determined to make H4895 work!!
FWIW, I will be trying the 253s full formed still with 62-63g H322 (DI) in the Ultralite. I may well stay with the 228s though. Any suggestions will be appreciated.
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Post by ballistic on Dec 5, 2021 17:28:27 GMT -5
I have lots of questions going forward. Without question, the scope levels will help. The following questions pertain to the larger, much more robust 40 cal Rem 700/RC barrel. 1) Two finger push down of the bullet. 1 finger and thumb, or more likely, 2 fingers on the top of the range/ram rod? 2) Using my comparatively light load of 73g H4895/278gAM (full formed 254, 4085 Hammer soon) with DI, would a duplex like 5g VV110/68-69g H4895 (more like a 76-78g H4895 load) be helpful at reducing the fouling that is occurring? I’m determined to make H4895 work!! FWIW, I will be trying the 253s full formed still with 62-63g H322 (DI) in the Ultralite. I may well stay with the 228s though. Any suggestions will be appreciated. Sew Im new to this forum but have been doing this for many years. My experience with a .416 (direct ignition Wlr primers)full sized and heavier bullets (350 grains) with 70 grains H4895 produced great groups and deviation- but it was horrible with building fouling in the middle of the barrel. Had to be patched between every shot. With my current .408: Direct ignition/60 grain chamber/Pittman 312 or 325 or fury 275. I’ve had the same issue with H4895 fouling the barrel (middle)badly. I tried brushing between shots and it still had issues. I gave up on it IMR4166/RL15/RL16 have all been much better. Joel Money is likely the guy for advice as he runs DI a lot and helped me settle in on some techniques using the powders listed. Btw-I love direct ignition and a powder chamber. I was determined to make H4895 work and I did - but wore a barrel out from cleaning between every shot. Best of luck-I’d like to hear what your magic combo ends up being -even it’s H4895………. Vic |
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Post by sew on Dec 6, 2021 16:57:47 GMT -5
Vic,
I doubt that H4895 will be involved in my magic combo.🙂. But, I’ll likely have a load using H4895 and just clean between. This is for hunting. I will be willing to go up to a little hotter loads to see if I can get a cleaner burn. FWIW, I also have a powder chamber and prefer DI.
Thank you.Steve
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Post by hillbill on Dec 6, 2021 20:03:39 GMT -5
I too had issues with 4895
with the 275 accumax it worked fine with great groups and fouling was decent
When I went to the 278 HC it was a no go
Some would keyhole
I abandoned that powder and load combo in favor of the FF 297 Hammer and RL-16 last season because I knew it worked
I really believe the 278 HC Fullformed would work with the 4895
No proof but just a strong hunch
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