I was testing some handloads today and my fps is anywhere from 50 to 150 fps faster then what the load data says it should be. I'm showing no signs of over pressure. Is this normal or should I be concerned. I was doing a ladder load test 3 rounds a peice from the start load to max all in .4 increments. And it did this on all the loads I tested.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Fps is alot different from load data
- Thread starter bungiex88
- Start date
boondocker385
New member
Does the recipe include info on their test weapon?
As a rule of thumb, I believe that if my velocities are over book, then so are my pressures. I have no way to prove this without pressure gages, but as a general rule, there is no such thing as a free lunch. If it is faster, than it is higher pressure.
This is a very difficult question. Physical signs are crude and inexact predictors of pressure. I do believe that sticking cases, blown or leaking primers, and loose primer pockets are 100% proof of an over pressure condition. But I also believe that you can be running "over pressure" loads and not experience these signs.
The cheap chronograph is a new tool that has only been around for the last twenty years or so, but for most pressure readings we are still back in medieval times, expecting that pressure is evidenced by physical conditions. Primer reading is no more reliable than reading tea leaves, but, in the transition from round to flat, you know something is going on.
I lubricate my test cases seeking to fully load the mechanism. When I see the transition from rounded to flat primers, I am confident that I am near, at, or over pressure. Dry cases in dry chambers provide anomalous primer readings. Also, parasitic friction between a dry case and a dry chamber hides over pressure conditions by reducing the load on the bolt. This happens all the time, guys develop loads with dry cases and dry chambers and they get a little oil on the chamber or case and then they start having stiff bolt lift. Well their loads were always overpressure to begin with, case-chamber friction reduced the load on the bolt, and fooled them into thinking their loads were under maximum. However, in recent testing in a 270 Win, I was getting velocities over 3100 fps with a 130 and bolt lift with lubricated cases were fine. The primers looked fine, everything seemed fine. Later I found some of the cases had slightly expanded pockets. Expanded primer pockets are 100% proof of excessive loads. I decided that velocities over 3000 fps were overpressure because pressures in load manuals are maximum just around that velocity.
For target shooting, I develop loads at the range, take my best guess as to whether they are over pressure or not, and then shoot them in matches. If I get sticking cases, leaking primers, then I know the load is too hot. Loads developed on the bench have shown over pressure conditions on warmer days, or days I have shot rapid fire, where the rifle gets a little warmer. If I get overpressure conditions, I cut the load. For a case about the capacity of a 308, I cut by half to a grain, until pressure indications stop.
This is a very difficult question. Physical signs are crude and inexact predictors of pressure. I do believe that sticking cases, blown or leaking primers, and loose primer pockets are 100% proof of an over pressure condition. But I also believe that you can be running "over pressure" loads and not experience these signs.
The cheap chronograph is a new tool that has only been around for the last twenty years or so, but for most pressure readings we are still back in medieval times, expecting that pressure is evidenced by physical conditions. Primer reading is no more reliable than reading tea leaves, but, in the transition from round to flat, you know something is going on.
I lubricate my test cases seeking to fully load the mechanism. When I see the transition from rounded to flat primers, I am confident that I am near, at, or over pressure. Dry cases in dry chambers provide anomalous primer readings. Also, parasitic friction between a dry case and a dry chamber hides over pressure conditions by reducing the load on the bolt. This happens all the time, guys develop loads with dry cases and dry chambers and they get a little oil on the chamber or case and then they start having stiff bolt lift. Well their loads were always overpressure to begin with, case-chamber friction reduced the load on the bolt, and fooled them into thinking their loads were under maximum. However, in recent testing in a 270 Win, I was getting velocities over 3100 fps with a 130 and bolt lift with lubricated cases were fine. The primers looked fine, everything seemed fine. Later I found some of the cases had slightly expanded pockets. Expanded primer pockets are 100% proof of excessive loads. I decided that velocities over 3000 fps were overpressure because pressures in load manuals are maximum just around that velocity.
For target shooting, I develop loads at the range, take my best guess as to whether they are over pressure or not, and then shoot them in matches. If I get sticking cases, leaking primers, then I know the load is too hot. Loads developed on the bench have shown over pressure conditions on warmer days, or days I have shot rapid fire, where the rifle gets a little warmer. If I get overpressure conditions, I cut the load. For a case about the capacity of a 308, I cut by half to a grain, until pressure indications stop.
Ambient air temps also factor in to actual FPS. Colder dense air = slower bullet speeds, warmer humid air = faster bullet speeds.
I use a chronograph and i'm learning to slightly adjust my powder charges to compensate for ambient air temps. For example i'll load up 41.9gr of W748 in the July heat , but to maintain the same velocity in November I need to bump it up to approx 42.2 .
I use a chronograph and i'm learning to slightly adjust my powder charges to compensate for ambient air temps. For example i'll load up 41.9gr of W748 in the July heat , but to maintain the same velocity in November I need to bump it up to approx 42.2 .
WVMountaineer
New member
You are shooting a longer barrel. So, faster is no surprise. Altitude wasn't the same. Humidity and temp wasn't the same, etc..... This is why serious bench shooters record all info when at a range session. Each of these will affect loads. Brass lots, powder lots, primer lots and brands will all differ from the published sources
As Snyper stated, deviation in your own loads will show from day to day as variables change. Not to mention the obvious differences in components. If no signs of pressure were evident and, it was accurate, no problems. God Bless
As Snyper stated, deviation in your own loads will show from day to day as variables change. Not to mention the obvious differences in components. If no signs of pressure were evident and, it was accurate, no problems. God Bless
I went to the range today, I threw some 125gr XTP loaded with H110. The data showed it going 1966fps. I was using a 4' GP100 357mag. My avg was 1530fps. I was hoping to reach buffalo bore 1603fps. I came close but still juat a tad short. Kinda blew my day lol. I'llhave to look for another set of data to try ans match Buffalo Bore!
Is this normal or should I be concerned.
It is normal, and you should not be concerned.
MV readings above or below published data are NORMAL.
Longer barrels generally turn in higher numbers than shorter ones, but this in not an absolute.
EVERY GUN & AMMO COMBINATION IS A UNIQUE INDIVIDUAL!
Some guns are "faster" than the general rule, some "slower".
I've seen 100fps difference between three different guns, all with the same barrel length, shooting the same ammo. Its not usual, but its not unheard of.
Published data are guidelines. They tell you what they got, an you should get something SIMILAR, but not exactly the same.
After all, what you are shooting is, at best similar, its not exactly the same, it can't be, if you are using your gun and your ammo.
Most test data is derived from very high quality target barrels with chambers and barrels cut to minimum specs. This results in pressure and velocity numbers that are usually higher than can be found in common production barrels with the same loads.
As others have said it is not unusual to see differences in speed with guns of equal barrel length. It is not unusual to see a 22" barrel shoot faster than a 24" barrel and I've seen as much as 130 fps difference between equal length barrels with the same ammo. That much is unusual, but 25-50 fps difference is very common. But what I normally see is one barrel getting just what the book says, and the other barrel being 25-130 fps slower than the manuals suggest. It is rare to see a barrel faster than the manuals suggest.
So it is NORMAL. Being concerned depends. If you're loading a mid-level load and are 50-150 fps over what is expected, but still under the expected velocity with a max load, then I'd not be concerned. If you are 150 fps faster than what is expected from a max load, I'd be concerned.
If the load data says that 60 gr of powder is a max load and to expect 3000 fps, then 3000 fps is the maximum safe speed (and pressure) in that individual rifle regardless of the powder charge. As you work up your loads you may hit 3000 fps with only 58 gr of powder, going up to 60 gr in that rifle could get you to 3100 fps with no visible pressure signs. It would still be overloaded, conventional pressure signs don't show until 70,000 psi, well above what is recommended.
In this case the 26" barrel could easily account for 50 extra fps with no increase in pressure. Considering the longer barrel I'd probably consider 100 fps over a warm load right at or slightly above max, but 150 fps over book max would cause concerns for me even without pressure signs.
As others have said it is not unusual to see differences in speed with guns of equal barrel length. It is not unusual to see a 22" barrel shoot faster than a 24" barrel and I've seen as much as 130 fps difference between equal length barrels with the same ammo. That much is unusual, but 25-50 fps difference is very common. But what I normally see is one barrel getting just what the book says, and the other barrel being 25-130 fps slower than the manuals suggest. It is rare to see a barrel faster than the manuals suggest.
So it is NORMAL. Being concerned depends. If you're loading a mid-level load and are 50-150 fps over what is expected, but still under the expected velocity with a max load, then I'd not be concerned. If you are 150 fps faster than what is expected from a max load, I'd be concerned.
If the load data says that 60 gr of powder is a max load and to expect 3000 fps, then 3000 fps is the maximum safe speed (and pressure) in that individual rifle regardless of the powder charge. As you work up your loads you may hit 3000 fps with only 58 gr of powder, going up to 60 gr in that rifle could get you to 3100 fps with no visible pressure signs. It would still be overloaded, conventional pressure signs don't show until 70,000 psi, well above what is recommended.
In this case the 26" barrel could easily account for 50 extra fps with no increase in pressure. Considering the longer barrel I'd probably consider 100 fps over a warm load right at or slightly above max, but 150 fps over book max would cause concerns for me even without pressure signs.
Ambient air temps also factor in to actual FPS. Colder dense air = slower bullet speeds, warmer humid air = faster bullet speeds.
I'm almost certain there are propellants that exhibit an inverse relationship, and there are some for which the manufacturer claims, at least, that the product is unaffected by ambient temp.
There have been a couple of cases, also, where "folks on the internet" seem to agree that some specific piece of data in some specific published manual contains a typographical error. I'd expect that to stand out, though, as a distinct and obvious data 'flier' that's a clear departure from a clear trend. I've never found one, but I'd have to think it's always at least remotely possible.
Got some more details since I posted last. My charge is 41.7gr the max load is 44.5 per nosler book it's 45.5 on the imr powder site. Now the book shows shooting from 24 inch barrel mine is 26 inch. I shot about 20 rounds of my 41.5 charge all same brass primers and bullet and the highest I got was 2750fps but my average is 2680 overall. In the nosler book it's getting 2700fps when there powder charge is at max which is 44.5. And I'm using the alpha master chrony so it probably has some error on its part to. Do you think I'm still safe.