Real FPS load vs Book value? MAX load values?

[Bigeclipse]

I have several threads going on about different issues so I apologize about the different threads. My other thread is concerning a 3006 load I have developed using a barnes 168gr ttsx under 50grains imr4064 using winchester primers. I measured it with my chrono and got 2550fps. My barnes manual states it should be at 2800fps. I know my barrel is a shorter mountain barrel but I did not expect to be so low. Does this sound right? I shot a factory remington corelokt 165gr and that got 2675 (they advertise 2800fps). I am wondering if my chrono is off or if it is my barrel really causing this slow speed? Barrel length is 22inches

Also do any of you try and go beyond book max load recommendations? if so, what is your process. thanks! also people say use your chronograph when approaching max loads and such...I am confused at what a chronograph is telling you other than speed.

 

[FearNoWind]

... I know my barrel is a shorter mountain barrel but I did not expect to be so low. Does this sound right? I shot a factory remington corelokt 165gr and that got 2675 (they advertise 2800fps). I am wondering if my chrono is off or if it is my barrel really causing this slow speed? Barrel length is 22inches

Also do any of you try and go beyond book max load recommendations? if so, what is your process. thanks!

Muzzle velocity is influenced by many things other than the barrel length. The type of powder, COTB length, bullet weight, bullet composition, all make a difference.

Chronographs can be eccentric. Depending on the manufacturer, quality, effects of ambient atmospheric conditions (amount and direction of light, temperature, etc) and distance from the muzzle can affect their accuracy.


Loading beyond reloading manual maximum recommendations is not uncommon. But it is not advisable. Reloading ammunition is very dangerous and even the most experienced reloader has suffered a damaged or destroyed firearm or serious personal injury while "playing around" with max loads. Furthermore, max loads listed in manuals are often more than the specific firearm you might be using can handle safely.

My recommendation would be to avoid trying to get something out of a rifle that it isn't designed to produce. Staying within safe load limits and trying different bullets with minor adjustments in OAL can often get you closer than running high pressure loads.

also people say use your chronograph when approaching max loads and such...I am confused at what a chronograph is telling you other than speed.

The chronograph is useful at virtually any point in load development. It not only provides you with information of muzzle velocity but it allows for you to calculate average velocities, extreme spreads and standard deviations for each load you might want to test. Using a chronograph when "approaching max loads", IMO, has no bearing as an isolated special function of the chronograph. Be careful who you rely on for ballistics information.

 

[Bigeclipse]

Muzzle velocity is influenced by many things other than the barrel length. The type of powder, COTB length, bullet weight, bullet composition, all make a difference.

Chronographs can be eccentric. Depending on the manufacturer, quality, effects of ambient atmospheric conditions (amount and direction of light, temperature, etc) and distance from the muzzle can affect their accuracy.


Loading beyond reloading manual maximum recommendations is not uncommon. But it is not advisable. Reloading ammunition is very dangerous and even the most experienced reloader has suffered a damaged or destroyed firearm or serious personal injury while "playing around" with max loads. Furthermore, max loads listed in manuals are often more than the specific firearm you might be using can handle safely.

My recommendation would be to avoid trying to get something out of a rifle that it isn't designed to produce. Staying within safe load limits and trying different bullets with minor adjustments in OAL can often get you closer than running high pressure loads.




The chronograph is useful at virtually any point in load development. It not only provides you with information of muzzle velocity but it allows for you to calculate average velocities, extreme spreads and standard deviations for each load you might want to test. Using a chronograph when "approaching max loads", IMO, has no bearing as an isolated special function of the chronograph. Be careful who you rely on for ballistics information.

thank you for your honest answer. I have been reloading 2 years now, handguns mostly, and have NEVER gone above a max load. Infact for my handguns I always stay close to minimum loads to aid in case life for plinking sessions. For rifles, I have only worked up loads for 2 rifles. My browning xbolt had FANTASTIC results at great speeds. I finally found a really accurate load for my mountain rifle but speed is lacking quite a bit but I have only tried a handful of loads with nosler partitions and a lot with the 168 TTSX. With both rifles and different loads I have always tested working my way up to the higher powder charges first to see signs of pressure. For my TTSX loads using imr 4064 I actually loaded .050 off lands, then worked all the way to book max with no signs of pressure. One odd thing was I experienced a slight flattened primer at 47.5 grains but 48, 48.5 49, 49.5, and 50 were all fine...