High velocity reading on the new chrony... - The Firearms Forum

jdon72 · 10-26-2010, 06:29 PM

Went to the range to test some new loads in 45 185 hp with the new chrony...and using unique with about 7.6 gr powder...i was getting an average of 1335fps...yes over 1300. The chrony was about 5 ft away. I think that is why i got heavy fps. I did find two casings that were split, but that could be from anything (it is reloaded brass). They were not overcharged.

With about 7.2 gr it was in the 800s.

Any opinions from other chronographers???

J

steve4102 · 10-26-2010, 07:03 PM

Quote:

The chrony was about 5 ft away.

Too close, set it at 12-15 feet and try again.

cycloneman · 10-26-2010, 07:05 PM

I dont know all that much about the 45. I do think that is smoking fast for a 45 tho. Are you sure the chrony was open all the way? Just throwing that out there. I am interested in seeing what some others say.

old semperfi · 10-26-2010, 07:07 PM

lymans 47th reloading hand book states that 7.8 grains of unique is maximum,so at 7.6 you are close.it also states for that max charge only 985 fps.you have something wrong.there is no 1300 fps vel. any where on the 45 acp.i would check my powder measure and scales before you have catastrafic failure.i would not suggest firing any more until you find the problem. old semperfi

312shooter · 10-26-2010, 07:07 PM

Did you test your chrony on any other known loads, maybe some factory stuff? What COAL did you use? It seems a little odd.

I sent some 230 FMJ's 1000 fps following Speer #14 data once because I seated FMJ's at a HP COAL. My chrony helped me realize why you always start at minimum loads and work up. Sometimes variable light conditions like low, fast moving cloud cover will screw with my chrony readings, other than that I'd back off those loads for sure.

JLA · 10-26-2010, 08:17 PM

Quote:

Originally Posted by steve4102

Too close, set it at 12-15 feet and try again.

+1. your chrony was being 'confused' by the blast from the pistol.

JLA · 10-26-2010, 08:18 PM

1300 is rowland velocities

jdon72 · 10-26-2010, 09:18 PM

I personally was excited. Shooting a 45 at over 1300fps...for the most part, no excessive pressure. I am sure it was too close...i was having many problems.

The lyman book is more for safety...i rarely see it going to max loads in other books and their test rounds are sometimes seated too deeply for what other manuals suggest. 7.8 is close to being high, but a couple others say 8.2gr is max.

They say if shooting subsonic, move it further back...that may be the problem. 45 is a subsonic round.

J

10-26-2010, 07:05 PM	#3
cycloneman Advanced Senior Member Join Date: Dec 2008 Location: Louisiana Posts: 7,406	Re: High velocity reading on the new chrony... I dont know all that much about the 45. I do think that is smoking fast for a 45 tho. Are you sure the chrony was open all the way? Just throwing that out there. I am interested in seeing what some others say. __________________ Who are you going to serve today?

10-26-2010, 07:07 PM	#4
old semperfi Advanced Senior Member Join Date: Aug 2009 Location: i live in southern indiana,old country boy at heart Posts: 1,506	Re: High velocity reading on the new chrony... lymans 47th reloading hand book states that 7.8 grains of unique is maximum,so at 7.6 you are close.it also states for that max charge only 985 fps.you have something wrong.there is no 1300 fps vel. any where on the 45 acp.i would check my powder measure and scales before you have catastrafic failure.i would not suggest firing any more until you find the problem. old semperfi

10-26-2010, 07:07 PM	#5
312shooter Advanced Senior Member Join Date: Mar 2008 Location: Las Vegas NV Posts: 1,148	Re: High velocity reading on the new chrony... Did you test your chrony on any other known loads, maybe some factory stuff? What COAL did you use? It seems a little odd. I sent some 230 FMJ's 1000 fps following Speer #14 data once because I seated FMJ's at a HP COAL. My chrony helped me realize why you always start at minimum loads and work up. Sometimes variable light conditions like low, fast moving cloud cover will screw with my chrony readings, other than that I'd back off those loads for sure. __________________ "Democracy is based on citizenship- perhaps the greatest gift the United States has given to the world- Power is vested in the people themselves, and government flows from the people" James M Henslin

10-26-2010, 08:18 PM	#7
JLA TFF Moderator/Host Join Date: Feb 2007 Location: Heart Of Texas Contributor Posts: 17,319	Re: High velocity reading on the new chrony... 1300 is rowland velocities __________________ It takes 43 muscles to frown, 17 to smile, and 3 for proper trigger squeeze. The latest caliber or gear is no substitute for experience and skill. Rifles and cartridges don't make hits -- shooters do. Fact of life: After Monday and Tuesday, even the calendar says WTF!

10-26-2010, 09:18 PM	#8
jdon72 V.I.P. Member Join Date: Feb 2009 Posts: 340	Re: High velocity reading on the new chrony... I personally was excited. Shooting a 45 at over 1300fps...for the most part, no excessive pressure. I am sure it was too close...i was having many problems. The lyman book is more for safety...i rarely see it going to max loads in other books and their test rounds are sometimes seated too deeply for what other manuals suggest. 7.8 is close to being high, but a couple others say 8.2gr is max. They say if shooting subsonic, move it further back...that may be the problem. 45 is a subsonic round. J

10-26-2010, 06:29 PM	#1
jdon72 V.I.P. Member Join Date: Feb 2009 Posts: 340	High velocity reading on the new chrony... Went to the range to test some new loads in 45 185 hp with the new chrony...and using unique with about 7.6 gr powder...i was getting an average of 1335fps...yes over 1300. The chrony was about 5 ft away. I think that is why i got heavy fps. I did find two casings that were split, but that could be from anything (it is reloaded brass). They were not overcharged. With about 7.2 gr it was in the 800s. Any opinions from other chronographers??? J -->