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With the coming of Summer, hunting possibilities change, typically for the better. Prairie dogs, ground squirrels, and gophers are all fair game. And so are pigeons, Eurasian doves, and house sparrows. Oh goody!

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Slugs vs. JSB's in the .25 FX Impact MKII

Started by Steelhead, January 08, 2022, 07:03:29 PM

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Steelhead

Steveoh and I had a casual shoot today at the dairy. Pesting is a bit tough due to the middle of winter with very few Euroasian doves and the whole place is a mudhole. We were supposed to go sturgeon fishing, but boat registration issues left us on the shore. The backup plan was to do some shooting and Steve had a prospective buyer in a friend of mine for one of his guns. Unfortunately, my friend declined to purchase the gun (the PCP factor with both cost and technical stuff made him second guess it, especially getting into it at age 78) However, it gave Steve and a chance to play with small bore stuff and do some good target work.

I decided to take advantage of the calm conditions and do a bit of ammo comparisons. What I found is that JSB's shoot much tighter groups than NSA slugs at 68 yards. Time and time again the slugs grouped at @ 1.25" to 1.5" and the JSB's were @ .75" to 1". Ironically the POI was virtually the same for both with maybe a click or two on the scope to adjust a 1/2", ut that's it.

It should be noted that I have the 'old version' slug liner barrel (shoutout to ArcherHMR for that, thank you). I've heard it mentioned that pellets won't perform out of the slug barrels. That is not so, at least not out of this one. I'm also running factory settings on everything and I chrony'd it at @ 912 fps (average with a variance of 4-5 fps)

I'm not disappointed at all; quite the contrary. I'm happy that I get such great performance from two different ammo sources without making any changes. I just found it interesting that the pellets are consistently better at tight groups. I found this helpful in having more confidence in pellets for smaller targets at distance (birds, rodents) but I would still use the slugs for bigger quarry (turkeys, small mammals) The larger 29 gr. NSA did not shoot better than the 26 gr. and groups at 68 yards were about 2" with about one in six being outside of that.

Perhaps some tuning can gain me some fps, but at what cost? Right now I'm laser-perfect with JSB's (and close to it with NSA's) @ 910 fps and I get somewhere around 65-75 shots before I fall off of the regulator on a 4k fill. Not sure I want to mess with it just to chase a number that doesn't show up on the paper target.
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Alan

I could elaborate about the various twists and about pellet vs. slugs. The reason being, I'm not as well know as the guy who recommended the twist rates—I knew he was wrong, but who would listen?

The newer slug liner is 1:17 vs. 1:23. As I recall, the pellet only liner is 1:27. In any case, the groups get smaller if the 1:17 is used. However, the pellets then take a back seat, as most spiral like a toy top on steroids!

Another issue I've noticed is that I get much tighter groups shooting over soft supports, than I do hard ones (bipods, etc.). Fact it, this is the main reason I didn't buy a tripod with a picatinny mount on top. I did buy a tripod shooting table of sorts, which I can use sitting or standing, and it is very stable as well.

Interesting comments Kevin, and more of less parallel my own.
Alan

I have a Hill EC-3000 compressor. If you're a fellow Guild member, and you pass through Roswell, NM, I'll fill your tank as a courtesy (4,250 PSI limit).

steveoh

Kevin had extremely interesting findings yesterday.  He compared JSB Match Diabolo Exact King .25 Cal, 25.39 Grains, Domed to Air Arms Diabolo Field .25 Cal, 25.4 gr pellets and found the JSB's to be a tiny bit more accurate. I have had the opinion based on a statement I'd seen somewhere that they were identical pellets as JSB manufactured the pellets for AA. How silly of me.

Also, Kevin shot some FX Hybrid slugs out of my Streamline for crummy groups. So that answers that question. The Streamline does not like slugs at all.

Great day hanging out, shooting, meeting Jerry, and mucking about in a sea of Adobe mud.

Was interesting putting a newby behind the Sumatra and the Impact. Jerry did well shooting both rifles, but seemed a bit nervous about the complexity and up front cost of a PCP with Air Tank. I get it and recall the learning curve of PCPs.  There's a lot to chew on, even with a well setup and accurate rifle ready to shoot.

Great day!

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Steelhead

I knew the Sumatra was accurate, but I honestly didn't think it was THAT accurate. What an awesome hunting gun for carrying around and when many shots aren't expected. The shot count isn't its strong suit, but accuracy, ease, beauty, and most of mobility are awesome. Stacking groups at 68 yards...yeah, pretty much. I wrongly thought that groups would be 1.5" to 2" based on...I dunno. Just didn't expect that kind of performance. A newfound respect for the venerable Sumatra.
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archerhmr

Kevin, I have never tested this, but have read that pellets do not like wind over 900 fps. I have shot some great groups myself at mid 900's and low 1000's. But never in the wind. This info is from some of the benchrest guys.

Steelhead

Makes sense and I have found that to be seemingly true when pesting. However, I went out today and knocked down to two starlings at 85 to 90 yards in a mild breeze. I DID compensate a tad, but not as much as I would have thought.

The irony is that what's the greater obstacle...a little breeze or the fact that the slugs are not as consistent? An honest question and in all reality we're not talking about pass/fail here. It's a luxury 'problem' as both shoot really well. I'm totally open to changing back and forth depending on my needs and I find that a arre luxury. What I'm happy about is the 'rediscovery' of the JSB performance as I have been shooting just NSA's for a long time.

It seems as if the twist rate on my slug liner is not as detrimental to pellets as the newer version. I just feel like I regain some confidence and accuracy and that feel great. Between the slugs being slightly off group-wise, and the fact that my scope had been a bit out I had taken a small backwards in confidence. I think I regained now. I should've done a paper session a long time ago to get my eye back.

Next time I'm going to a comprehensive dope chart/comparison between NSA's and JSB's from short range (30 yards) to long range (125 yards). Going further isn't fair IMO when talking pellets and I still think that's a poke&hope shot regardless; certainly not a gimme with either ammo on a bird-sized target.
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Alan

It is all in the twist rate I suspect. I've tried to use the standard Superior barrel with the NSA slugs, and they shoot a-ok, as do pellets. But the Superior made for heavier slugs (1:17), throw pellets all over the target even at 25 yards.

One I things I am going to buy, is the shroud tuner device. One thing "my" Impact doesn't like is hard mounts (bipod atop my bench). Over bags, it is just fine.
Alan

I have a Hill EC-3000 compressor. If you're a fellow Guild member, and you pass through Roswell, NM, I'll fill your tank as a courtesy (4,250 PSI limit).

steveoh

Quote from: Alan on January 10, 2022, 03:54:09 AM
It is all in the twist rate I suspect. I've tried to use the standard Superior barrel with the NSA slugs, and they shoot a-ok, as do pellets. But the Superior made for heavier slugs (1:17), throw pellets all over the target even at 25 yards.

One I things I am going to buy, is the shroud tuner device. One thing "my" Impact doesn't like is hard mounts (bipod atop my bench). Over bags, it is just fine.

I swore off bipods for a while because I got much tighter groups over bags. Kinda interesting and curious.
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Steelhead

The ol' bipod controversy....I find that I do better with small bore on a bipod but with a big bore I do better from a softer rest. My initial thoughts (based on nothing more than intuition) is that the recoil and 'bounce' of the big bore has more of effect off of the bipod than the small bore.



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steveoh

Quote from: Steelhead on January 10, 2022, 06:55:25 AM
The ol' bipod controversy....I find that I do better with small bore on a bipod but with a big bore I do better from a softer rest. My initial thoughts (based on nothing more than intuition) is that the recoil and 'bounce' of the big bore has more of effect off of the bipod than the small bore.

I thought about this after our shoot. The mile long Citrus is way more capable of good groups, but on the bipod I think the synchronicity of pulling the trigger and all that violent action of the spring and hammer, muzzle climb, forward /backward action of the rifle and the janky cheap bipod had too much going against it. I think I had a bit of flinch too.  I've gotten way better groups. It is for sure a bag gun. Seems that the DAQs are the same.

Where did I put my bags? Hmmmm.
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