Originally posted by StoneHendge
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16" factory ammo velocities confirmed on film
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Originally posted by 458MinMag View PostOne more data point, apparently on the low end... 123 Amax factory loads clocked 2387fps average out of my 16inch.
There are 14.5" and even a cut down 13.7" Grendels that shoot 123gr Hornady at 2420fps, but on a warm day.
2387fps makes sense for a barrel that doesn't pressure up as fast, or winter temps. There are some barrels that use rifling that isn't as sharp as Enfield rifling, and have enough variation from the average to not pressure up as quickly.
I have some chrono readings through my 16" using PF 123gr Moly Scenars as follows:
2522
2484
2582
2518
2503
2522fps average on a warm day with that load. Then the next spring with the same load, same rifle:
2447
2451
2454
2456
.792" group, 2452fps average
The first time I chrono'd Hornady AMAX with it on May 25th, 2013
2365
2470
2422
2470
2460
2439fps avgNRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
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"temp at time of chronograph reading can make a pretty good difference as well. would be nothing for the same ammo in the same gun to be 40 fps faster on a
90 degree day as a 32 degree day "
Those lots had quite a difference. Used a lot that magnetto'd at 2440 on day 1 of a long range class. On day 2, started truing up at 800 yards. Everything looked good .... then I unknowingly started using a box of the other lot. Everything started sailing high over the truing bar. Instructor redid my card. Then I unknowingly went back to a mag from the other box and started putting everything in the dirt in front of the bar. There was a lot of head scratching that afternoon. Didn't realize what the problem was until I checked my boxes back at the motel that night. Luckily, I had enough of one lot to get me through day 3.Last edited by StoneHendge; 08-11-2017, 08:17 PM.Let's go Brandon!
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Originally posted by LRRPF52 View PostWhat temperature outside?
There are 14.5" and even a cut down 13.7" Grendels that shoot 123gr Hornady at 2420fps, but on a warm day.
2387fps makes sense for a barrel that doesn't pressure up as fast, or winter temps. There are some barrels that use rifling that isn't as sharp as Enfield rifling, and have enough variation from the average to not pressure up as quickly.
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Originally posted by 458MinMag View PostIt was 75 or 80deg that day, so it must be lot-to-lot variation in the ammo, or the individual barrel as you mentioned. I'm not at all worried about it. I've got some Honrandy Black and 123 SSTs that I'll check in the future just to see where they fall. I also shot some handloads with 123 Amax and CFE223 ... 31.2gr gave an average of 2349fps over my Magnetospeed.
That exact same load from my 16" with a 123 eld-m at 2.255 in hornady brass with a CCI 450 gives me just under 2500.. my notes confirm my average was 2489.. what make and twist barrel is it?
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Originally posted by 458MinMag View PostWow, your's is shooting a lot faster! Very nice. I didn't mean to get your thread sidetracked; I clearly have an outlier or chrono issues. Carry-on!
Guys have been shooting and hunting with guns and cartridges they love for decades not ever shooting over a chrono or caring about velocity. If it puts the the bullet where you are pointing is first and foremost.
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Originally posted by Kilco View Post31.2gr CFE223 over a 123 out of a 16" gave you 2349?!
That exact same load from my 16" with a 123 eld-m at 2.255 in hornady brass with a CCI 450 gives me just under 2500.. my notes confirm my average was 2489.. what make and twist barrel is it?
- PA
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Originally posted by 458MinMag View PostIt was 75 or 80deg that day, so it must be lot-to-lot variation in the ammo, or the individual barrel as you mentioned. I'm not at all worried about it. I've got some Honrandy Black and 123 SSTs that I'll check in the future just to see where they fall. I also shot some handloads with 123 Amax and CFE223 ... 31.2gr gave an average of 2349fps over my Magnetospeed.
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When you have a longer throat, it won't convert the powder as fast, so that initial peak takes longer to rise, but you can chase the throat with COL of course limited to what your mag will allow.
When I load a 123gr AMAX to 2.275" in that same 16" AA barrel with SAAMI chamber on 31.2gr of CFE at 60˚ F, I got 2500fps.
In my Lilja 17.6" barrel with SAAMI chamber, I got 2465fps at 31.7gr of CFE loaded to 2.260" COL with the same 123gr AMAX at 64˚ F.
At the end of the day, I don't care to much, just load up my 31.2gr CFE load under 123gr AMAX double-weighing charges, and head to the range or field with steel targets in mind. I have zero desire to jack around at 100yds with a known load that shoots into the head of an IPSC at 500yds easily, and smokes my 12" poppers at 700yds so that after a few rounds, I'm looking for more range. 1100yds is more of a challenge with 123gr AMAX for me.NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
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I'm happy to take this up, actually...just gotta find some Hornady 120 gr SST for each first...though the Grendel does seem to have a LOT more options in this bullet weight. I was planning on doing some load testing a development in each caliber anyhow. Frankly, I don't expect a lot of difference...
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