Velocity varience
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Velocity varience
Shot my very first bunch of 9mm this morning. 9mm, 147gr lrn, 3.2 gr Titegroup, col 1.113. Velocity ran from a low of 954fps to a high of 990fps. Most were from 960 to 980fps. Is this typical? I was expecting figures a little closer. To compare, i shot some Blazer factory ammo, 115gr and they varied nearly 30fps from 1064 to 1095fps. Thanks
- GasGuzzler
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Re: Velocity varience
I still haven't set up the chrono I bought nearly two years ago but to me that's not all that odd for such a short piece of brass and a way heavy for cartridge bullet in a cartridge known for variations in brass thickness and brass length.
(That's a long sentence)
I haven't used that powder or that bullet but my pet 9X19 load is quite a bit longer than that with a 115gr bullet.
Might help to know barrel length and action type too but 50 FPS ES doesn't sound bad for 9mm.
(That's a long sentence)
I haven't used that powder or that bullet but my pet 9X19 load is quite a bit longer than that with a 115gr bullet.
Might help to know barrel length and action type too but 50 FPS ES doesn't sound bad for 9mm.
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Re: Velocity varience
It's probably not a good idea to try to compare bullet velocities when such varied weights are considered. It looks to me that the velocities of the "heavies" are probably within spec for the bullet weights. Then, I've never used TightGroup powder ....
jd
jd
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Re: Velocity varience
That's just 36 fps .
I've had a lot worse results than that .
The larger the sample size is the smaller the variations will be by average .
If you have consistently high and low velocities rather than a group somewhere in the middle with outlayers then you may have a point to look at for a change .
Case variation can cause the changes .
Are your bullets commercial cast , commercial swaged or home cast ?
Differences in commercial cast voids , wrinkles , pour consistency etc will easily cause that much difference in speeds . Any of these can cause a bullet to be as much as 5gr light .
Swaged is about as good as a LRN gets for consistency .
If they are your home cast and display any of line 1 above a few minor changes can help get you more consistent .
A seldom considered possibility is whether or not one lot of brass was cleaned .
I don't sweat the autos smaller than 40 for match prep . As 90% of that ammo is for training and plinking . I have the 9 and 40 down to all WIN . Matching headstamp is a good place to start . But it sounds like you're already doing that .
As to casting , I haven't been doing it forever . I have several Lee moulds that I cast 125,158 gr bullets +- 1.5 gr being 6 cavities it is possible the half of that is cavity variation .
I ran some 90 gr in an NOE with 85 of 100 being +.7 to -.3 gr very good for a 5C mould .
I ran some 45 cal last week that cast a PB at 414 gr and a hollow base at 380 gr with a heavy weight of 414.7 and 380.9 and a low of 413.6 and 379.6 . From 25 pours I kept 19 of the PB and had a core group of 414.0-414.3 and 21 of the HB with a core group of 16 of which were were 380.1 gr . This from a brass 2 cavity with interchangeable base pins that costs $120 and comes from Slovenia .
That's a lot to digest . For.a first run you did well .
I've had a lot worse results than that .
The larger the sample size is the smaller the variations will be by average .
If you have consistently high and low velocities rather than a group somewhere in the middle with outlayers then you may have a point to look at for a change .
Case variation can cause the changes .
Are your bullets commercial cast , commercial swaged or home cast ?
Differences in commercial cast voids , wrinkles , pour consistency etc will easily cause that much difference in speeds . Any of these can cause a bullet to be as much as 5gr light .
Swaged is about as good as a LRN gets for consistency .
If they are your home cast and display any of line 1 above a few minor changes can help get you more consistent .
A seldom considered possibility is whether or not one lot of brass was cleaned .
I don't sweat the autos smaller than 40 for match prep . As 90% of that ammo is for training and plinking . I have the 9 and 40 down to all WIN . Matching headstamp is a good place to start . But it sounds like you're already doing that .
As to casting , I haven't been doing it forever . I have several Lee moulds that I cast 125,158 gr bullets +- 1.5 gr being 6 cavities it is possible the half of that is cavity variation .
I ran some 90 gr in an NOE with 85 of 100 being +.7 to -.3 gr very good for a 5C mould .
I ran some 45 cal last week that cast a PB at 414 gr and a hollow base at 380 gr with a heavy weight of 414.7 and 380.9 and a low of 413.6 and 379.6 . From 25 pours I kept 19 of the PB and had a core group of 414.0-414.3 and 21 of the HB with a core group of 16 of which were were 380.1 gr . This from a brass 2 cavity with interchangeable base pins that costs $120 and comes from Slovenia .
That's a lot to digest . For.a first run you did well .
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Re: Velocity varience
I shoot a 135-grain lead, gas checked bullet in my 9mm Luger. I've been shooting it with HS6 as of late. SD runs 15 FPS and ES 47 FPS.
Honestly, with a self defense handgun, I don't give a rip about the nummies. What I want to see is dependable ammo that shoots ragged holes (cutting through each other) at self defense distances. This ammo does.
Honestly, with a self defense handgun, I don't give a rip about the nummies. What I want to see is dependable ammo that shoots ragged holes (cutting through each other) at self defense distances. This ammo does.
Michael
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Re: Velocity varience
If I were on a PC (instead of my phone) I'd give that a thumbs up.Ranch Dog wrote:I shoot a 135-grain lead, gas checked bullet in my 9mm Luger. I've been shooting it with HS6 as of late. SD runs 15 FPS and ES 47 FPS.
Honestly, with a self defense handgun, I don't give a rip about the nummies. What I want to see is dependable ammo that shoots ragged holes (cutting through each other) at self defense distances. This ammo does.
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Re: Velocity varience
GasGuzzler wrote:If I were on a PC (instead of my phone) I'd give that a thumbs up.Ranch Dog wrote:I shoot a 135-grain lead, gas checked bullet in my 9mm Luger. I've been shooting it with HS6 as of late. SD runs 15 FPS and ES 47 FPS.
Honestly, with a self defense handgun, I don't give a rip about the nummies. What I want to see is dependable ammo that shoots ragged holes (cutting through each other) at self defense distances. This ammo does.
I'm in agreement and got the thumbs up for ya.
“Good judgement is the result of experience and experience the result of bad judgement.”
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― Mark Twain