Handloads are mid-air tumbling

Reloading info for the 5.7x28mm

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waffentomas
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Handloads are mid-air tumbling

Post by waffentomas » 24 Jan 2017, 13:04

Just got back from the range and had maybe 20%-ish of my handloads are showing signs of instability at 30 feet.

A lot of clean holes, but some noticeable canted entries.

Two loads fired today, same bullet:

Hornady 55gr JSP
BC .235
OAL .705
Once fired brass
CCI 400 primer
OAL 1.585

First was:

4.2gr 800x about 1305 fps

Second:

3.6gr Longshot about 1180 fps

No odd signs of pressure or, at that range to 40 ft., no wildly inaccurate flyers.

I've been reloading 25 years or so, and have seen this on occasion with other calibers, usually with cheaper copper washed bullets like Berry's.

Berger's twist rate calculator rates these loads at around a 1.95, which is 'stable'.

Any thoughts?

Federal 40gr and FNH 40gr VMAX seem to fly straight.
Last edited by waffentomas on 24 Jan 2017, 15:18, edited 1 time in total.

DoubleJ
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Re: Handloads are mid-air tumbling

Post by DoubleJ » 24 Jan 2017, 15:03

Heat them up a bit, I've gotten 55s up around 1500, and I've heard rumors of them into the 1800s. Not sure if you can get there with those powders, haven't tried them, but I've gotten all round holes in the 1400s. All barrels are different though, you might have one on the slower end of the twist rate. Also heard a rumor recently about FN changing the FsN twist rate, but I don't recall the details.

Toaster
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Re: Handloads are mid-air tumbling

Post by Toaster » 24 Jan 2017, 16:19

What way did you hear they were going with the twist in the barrel?

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Re: Handloads are mid-air tumbling

Post by panzermk2 » 24 Jan 2017, 16:53

Switch to Hornady 50gr SP. This is why years ago I stopped using 55gr bullets and switched to 50gr Hornady SP for all three of EA's Sub Sonic loads.
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grimmond
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Re: Handloads are mid-air tumbling

Post by grimmond » 25 Jan 2017, 19:07

FNH must have their finger on the magic powder/bullet combo. According to their flier the SB193 is a 62gr fmj. It does not specify if its designed for use in only the PS90 or FSN. I myself seem to have no issues creating stable subs using 55gr fmj bullets. I haven't done very much testing with 62gr bullets yet though.
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Toaster
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Re: Handloads are mid-air tumbling

Post by Toaster » 25 Jan 2017, 21:18

It seems FN uses very long lightweight rear biased bullets.

Most of the offerings we see are not long enough. Or too heavy. Or not biased.

Jay does not consider a tighter twist barrel or suggest powders/loads from what I've seen. He still hasn't released any info about his brass he released. Prices jumped into further crazy regions, doesn't respond to emails, my barrel is still nowhere to be seen. I've lost interest in the accurizing service almost completely, and sights, or any additional sales with what I've experienced so far..

I don't think there was any magic, science and skill more likely. They know what they're doing.

shopsmart
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Re: Handloads are mid-air tumbling

Post by shopsmart » 31 Jan 2017, 12:09

I have tried out 62 gr subsonics with mixed results. Been on the back burner project for awhile now. Stabilization was "ok" but cycling was the issue. Only PS90 sbr.

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Re: Handloads are mid-air tumbling

Post by Buffman » 31 Jan 2017, 20:29

grimmond wrote:FNH must have their finger on the magic powder/bullet combo. According to their flier the SB193 is a 62gr fmj. It does not specify if its designed for use in only the PS90 or FSN. I myself seem to have no issues creating stable subs using 55gr fmj bullets. I haven't done very much testing with 62gr bullets yet though.
They were using 55gr sierra match king bullets at one point.

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grimmond
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Re: Handloads are mid-air tumbling

Post by grimmond » 31 Jan 2017, 21:45

Yes, at one point they did use 55gr sierra match king bullets. But that was back during the days before the mkII came out. The current flier you can download lists it as a 62gr. So as I said before, they have the magic combo. So something has obviously been changed to make that workable. Can anyone prove what the current twist rate is in the MKII? Or better yet can someone get FNH to give a written statement as to if its only for use in the PS90? Over the phone and verbal communication means absolutely nothing in this day and age to me.
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Toaster
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Re: Handloads are mid-air tumbling

Post by Toaster » 02 Feb 2017, 16:06

I dont believe in Magic


I'll start trying to get some Subsonic 62 grainers to cycle a stock MKII... a tighter twist would sure help!!!!........

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