|
|
Joined: Dec 2007
Posts: 1,841
Campfire Regular
|
OP
Campfire Regular
Joined: Dec 2007
Posts: 1,841 |
In particular, my pet load for my favorite rifle is 1 grain under max powder charge, yet my lab radar results show velocities are 190fps over what the book says. Same barrel length. H1000 powder. Also verified on traditional chronograph.
Another rifle with RL22 is 100 to 150 over book velocities with under book charge. Same rifle with factory ammo is 110 under stated on box. So it's not just the lab radar.
I have another rifle that is 150 under book velocity with a max load.
Are the books that unreliable, or is just the combination of rifle, bullet, setback off the lands and powder charge with those cartridges giving me better or worse results?
Zero signs of pressure on any of the loads.
Salmonhead
|
|
|
|
|
Joined: Nov 2011
Posts: 30,859
Campfire 'Bwana
|
|
Campfire 'Bwana
Joined: Nov 2011
Posts: 30,859 |
If there was no variance from book there would be no reason to buy a chronograph.
What you are seeing is not unusual.
You didn't use logic or reason to get into this opinion, I cannot use logic or reason to get you out of it.
You cannot over estimate the unimportance of nearly everything. John Maxwell
|
|
|
|
|
Joined: Jul 2004
Posts: 6,654
Campfire Tracker
|
|
Campfire Tracker
Joined: Jul 2004
Posts: 6,654 |
Do you have John's book, The Big Book of Gun Gack? If so reread Chapter 8, if not get it. Then get Gack 2, you'll find them to be very helpful.
'Four legs good, two legs baaaad."
----------------------------------------------
"Jimmy, some of it's magic,
Some of it's tragic,
But I had a good life all the way."
(Jimmy Buffett)
SotG
|
|
|
|
|
Joined: Dec 2007
Posts: 1,841
Campfire Regular
|
|
OP
Campfire Regular
Joined: Dec 2007
Posts: 1,841 |
Dont have, will get. Thanks.
Salmonhead
|
|
|
|
|
Joined: Jun 2004
Posts: 11,114
Campfire Outfitter
|
|
Campfire Outfitter
Joined: Jun 2004
Posts: 11,114 |
Speed is a pressure sign.
Tight chambers produce more pressure and more speed. The bullet has no place to get speed from, other than gas pressure.
Some reload data is generated in test barrels, which have very tight chambers. That gives conservative load data for normal chambers. Other data is generated in off the shelf firearms. It pays to know the source of the data you are using.
Be not weary in well doing.
|
|
|
|
|
Joined: May 2007
Posts: 5,732
Campfire Tracker
|
|
Campfire Tracker
Joined: May 2007
Posts: 5,732 |
I have only 1 rifle with an “unexpectedly fast” barrel. Like your 2nd example, it’s with R22.
74.5 grains was getting 165 grain TTSX pills to just over 3,200 fps in that .300 WM. (Federal brass, Rem 9.5 Mag primers). I just left it at that & thanked my ballistic good fortune, rather than attempting to wring any more from it.
I then “upgraded” to Nosler brass, and the same recipe “only” got 3,160 fps. I can live with it.
I wanna say it was JB who said, “There are fast barrels, but there are no magically fast barrels.”
Only a couple other of my rifles reach book speeds, and most are appreciably below. I’m content enough to punch paper & kill critters while keeping the entirety of my fingers & vision.
FC
"Every day is a holiday, and every meal is a banquet."
- Mrs. FC
|
|
|
|
|
270 members (10gaugemag, 10Glocks, 257 mag, 12344mag, 01Foreman400, 1lessdog, 32 invisible),
1,381
guests, and
1,083
robots. |
|
Key:
Admin,
Global Mod,
Mod
|
|
|
Forums81
Topics1,190,225
Posts18,447,570
Members73,899
| |
Most Online11,491
Jul 7th, 2023
|
|
|
|
