.30 Cal Ammo Shootout: BC's and other stuff measured!

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SMH77

SMH77

Member
Oct 28, 2017
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Wisconsin, United States
Just as a PSA, I figured I’d share with you the results of my measurement today of 3 of the best pellets in .30 caliber: the JSB .30 cal light (44.75 grain), the JSB Heavy (50.15 grn), and the new H&N Baracuda (46.30 grn) pellet. Pellets were not measured and were taken straight out of the tin without sorting for weight. No sorting for head sizes was complete either.
Muzzle velocity, near was taken with the rear window of the chrony at 1 yard from the tip of the moderator
Distance to far measurement, was taken with the rear window of the chrony at 50 yard from the tip of the moderator
Delta (distance) between locations: 49 yards (measured with a Nikon laser rangefinder with angle compensation)

I opened up Chairgun (Mac version) and adjusted the environmental conditions, altitude, etc. I then went to the BC calculator app, plugged in the data, and calculated the following results (below). I was actually surprised to see how well the H&N did for it's BC. It also seemed to shoot fairly tight groups at 50 yards also.My gun: RAW HM1000x, setup in .25 caliber, with a LW polygon barrel, swapped the barrel and probe to configure in .30 cal. .30 cal barrel is a Lothar Walther traditional rifled barrel (no idea of the twist rate).Notes: same chrony was used at both distances. Velocities data is shown below. I hope this is helpful information for anyone looking for data from this gun / setup? If so, and you appreciate the time / effort, please take a minute and leave me a '+' (it's just a small way that seems to be a decent 'payment' for the time to measure and share the data, and it makes me feel like I'm helping contribute to the forums, LOL). :)

First up: The JSB Lite Pellets (44.75 grain):
1524244759_17792728915ada2117f03817.10669398_30 Cal JSB Lite 44.75 grn BC Results 04-20-2018.jpg


Next up: JSB Heavy Pellets (50.15 grain):
1524244818_12644443205ada21528e33f2.60153247_30 Cal JSB Heavy 50.15 grn BC Results 04-20-2018.jpg


Last up: the H&N Baracuda Pellets (46.30 grain):
1524244846_11856509765ada216e014513.35991366_30 Cal H&N Baracuda 46.30 grn BC Results 04-20-2018.jpg


And the RAW data (pun intended, LOL):
1524244888_7029674535ada2198211f25.21039227_30 Cal BC Test at 45F, Raw Data.jpg


I have pictures of the 9 shot groups at 50 yards for each pellet too that I can also post...
Sean
 
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Sorry, I was out and about, and didn’t have time to post the measurements for the groups. So I’ve posted them below. Comment: the first three groups I shot and let the point of impact be wherever it was sighted in at (left, slightly-obviously). To keep things consistent, I juat shot them all the same. When I move the chrony back to 50 yards (see photo below), I set it up to read with the pellets striking on center. I took my first shot and confirmed it was still ‘left’ so I held over .3 Mil to the right to center the group, and shot the following 8 shots (JSB lites) with the holdover dialed in manually. Hence the reason for the 8 shot group, mixed in with the other 9 shot groups (the one lone shot was NOT a flier...).

Anyway, here are the groups with measurements:

JSB Lites:

1524258584_11709500585ada57184f2e97.33331535_65BF5DBD-165B-4B05-BB91-29BCEB14DE31.jpeg


JSB Heavies:

1524258614_365550545ada5736987b08.09204121_ABA19809-4A2D-4CB5-80B6-5B211D54679E.jpeg


H&N Baracudas:

1524258648_6959004975ada5758ccee72.00955764_002DC6F3-EE5B-4D01-B041-E952746A872E.jpeg



8 shot group of JSB Lites:

1524258679_12671130425ada5777c11ad4.64700794_20ED337A-2C71-4474-AE50-307FDBB737FE.jpeg


Chronograph set up to take the 50 yards readings:

1524258760_20977516365ada57c825a7e6.96524428_999643F9-3977-4571-8D52-E8DA0191E265.jpeg
1524258761_4441442935ada57c9e90c67.86457385_C984713F-8451-40CA-B8B5-806398B736D5.jpeg
1524258763_9023945065ada57cb9ffaf8.87821733_0B62B9CA-77E3-4CDF-8FF2-DA4FBE3B2A19.jpeg



Sean
 
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Good observation. Here’s what is different and likely the cause of the difference you are seeing: it was 21F outside back then vs 45-50 (rapidly warming up), which will being the BC up somewhat (it varies with temp); 2) the first test was from muzzle to 43.8 yards, which also causes the BC to be lower (it tends to improve with the further distance).

I spent a lot of time reading Yrrah’s (Harry) posts, and noted that there are some transitional effects that happen within the first 12 inches or so of leaving the muzzle, that can cause a bit of difficulty (or inconsistency) when trying to measure it there. To make a long story short, I’ve setted in on testing at 1 yard, and 50 yards to catalog the BC’s for those reasons.

I also plan to test over different temps to determine the temperature effects as well.

Good eye! That’s my theory anyway...


Sean
 
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Thanks. Appreciate the effort. I’ve been meaning to do this with my .30 FX Bobcat Mk2 at 885 FPS Lite and 850 FPS Heavy. ST barrel. Will use close to same distances as you. Swamped now with home move but should get it done mid May. I really am trying to decide which pellet for EBR in October. Now I guess I also have to test the H&N...
;)
Mike 
 
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I’ve read Harry’s articles also, very informative. I think he said that BC lowers when you get to 80 to 85% speed of sound, which for 80% would be about 910 FPS. As speed lowers from there it appears to be stable (at the top of a bell type curve) until it reaches a certain lower speed and BC then starts decreasing. At least that’s the way I understand it. I’m sure pellet shape, weight, size, spin, and stability all also figure into the math...
 
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"Centercut"I’ve read Harry’s articles also, very informative. I think he said that BC lowers when you get to 80 to 85% speed of sound, which for 80% would be about 910 FPS. As speed lowers from there it appears to be stable (at the top of a bell type curve) until it reaches a certain lower speed and BC then starts decreasing. At least that’s the way I understand it. I’m sure pellet shape, weight, size, spin, and stability all also figure into the math...
Click to expand...
Yeah, Harry's writings are very informative, but the are a bit spread around in all sorts of threads-so I'm not sure I've put together the whole picture. Thanks for sharing that information. The one thing I think I'm pretty certain of is that BC increases with increasing temps-I'm hoping the testing I'm doing will help to flesh that out a bit (now that I have an established procedure for testing).


Sean

 
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Adding a summary chart like I placed in the .25 cal ammo shootout with the BC's and group sizes listed at the bottom. I also followed the same approach and removed the top and min and max, using the 'mid-7' data to calculate the averages to calculate the BC's.

1524455413_18860627665add57f5f05351.30370373_30 Cal BC of 3 pellets, compared.jpg


It's surprising how well the .25 caliber JSB Heavies do (BC wise) compared to even the .30 caliber pellets. However, it's clear that the .30 cal accuracy outperforms the .25 cal almost across the board. Having said that, the speeds are a bit lower too. I'll have to play with bumping up the speed on the .30 cal's to match the speeds of the .25 cal pellets (down the road) to see of the accuracy holds up.
 
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