Just how fast is too fast?

coldmaker

coldmaker

Regular
Rating - 100%
32   0   0
I have a new to me rifle in 270 win
based on a Carl Gustaf 1900 action with custom 22" barrel of unknown brand.
it looks short throated as max coal with the 130 hornady interlock sp is 3.305”

loaded at 3.285” i got velocities of 3100 fps with a clean barrel at 4°c with 60gr H4831sc
and 3145 average at -8°c with a fouled barrel (after about 60 shots without cleaning)

most data i found were giving around 3020 fps with a 24" barrel.
the fastest i saw was nosler load data at 3124fps with 59 gr as max.

i don’t see any of the habitual pressure signs
easy bolt lift,
great looking primer ( maybe very slight cratering that you almost need a magnifying glass to notice)
no ejector marks.

i was wondering if the above average speed alone must be considered a pressure sign in itself
with all the other rifles i loaded for, i normally had to go over max to get book velocities...

i would like to keep this load as it shoot around 0.75-.0.8" at 100y
the 6 shots i chronoed averaging 3100 out of a clean barrel had an ES of 7
and the 6 with a fouled barrel averaging 3145 had an ES of 8
both had an SD of 4.

will try a 10 shot string next week
 
If it shoots good I wouldn’t be scared of 3100 FPS. Chrony it again when it is hot out to be sure you don’t see pressure signs. Sounds like a nice rifle and a great load.
 
If you take a shot at a target and you see 3-4 holes in it, not just one, you have officially exceeded all loading parameters and guidelines and limits etc and you should check your scales for being out of balance. How do I know this, you ask ???
I loaded some Sierra Gameking 150gr .30 cal in my .300 WinMag and was using an el cheepo electronic scale from frankford arsenal and it was telling me I was loading 72 gr of IMR 4350 when it was actually letting me put 78gr of the stuff in there. Shoulda clued in when I seated the bullets and sounded kinda crunchie. I didnt have a chronograph at that time and thank god I only fired the 1 round and figured something was not quite kosher. Bolt lift on the ruger mk1 was normal but the primer was flattened out like somebody had poured liquid metal in the primer hole and let it set up. Case head had major bright marks all around the primer. Got home and pulled out my old lee safety scale and pulled 5 bullets out of their cases and weighed each powder charge. Had to have a good stiff shot of whiskey after that and I took a hammer to that stupid little frankford digital scale.
 
tim3500 said:
Told ya that that gun will shoot ! Seems like your enjoying it.
Click to expand...

yes, the 1900 action is incredibly smooth cycling.
accuracy with factory 130 rem corelokt and 140 hornady btsp wasn’t great at around 1.5-2.5"
but it’s been pretty easy to get the 130 hornady SP to group slightly better than MOA.

will try other bullets later. i already have a box of 150 interlock on hand i want to try soon.
 
Don't worry about the speed, as long as there is no sticky bolt lift or other pressure signs. I'm getting similar velocities out of my 22" .270. I ran into pressure signs at 61.5 grains H4831sc with 130s. Unmistakably sticky bolt lift, the primers looked like all the rest.

Sounds like you have a great load right where you are at 60 grains if accuracy is acceptable!
 
You can't get more speed without more pressure. If you are using the same barrel length, and same components as your manual, and the speed is faster, the pressure is more than the max that your manual suggests. No way around that. A good article that explains why and how is written by John Barsness, and an excerpt of his writing follows:

"IF your rifle gets higher than normal (reloading manual) velocities with a certain bullet and powder, then the pressure is almost certainly higher than the manual's pressure. (The exception: Some manuals first work up a load in a pressure barrel, then chronograph it in a sporting rifle, which may or may not have similar chamber/bore dimensions. This data is flawed.)

This NOT mean that because a certain load gets 2800 fps in my rifle thait gets 55,000 psi, or that it is safe in your rifle. All it means is that it gets approximately the same pressure (given the same bullet--not some other manufacturer's of the same weight) as the load in the manual in YOUR rifle.

Also, there has to be an allowance made for the barrel length. 25 fps per inch is close enough.

This concept has been proven many times with pressure equipment. If a 165-grain XYZ bullet is listed in the manual with 55 grains of 1234 powder at 2800 fps in a 24" barrel, then if your 24" barrel only gets 2600 fps with the same combination then your pressure is lower. If your barrel gets 3000 fps then the pressure is higher, and probably too high.

Pressure and velocity are indeed tied together, a simple fact of phsics. This is the reason that a chronograph is a much better measure of SAFE (not absolute) pressures than any of the traditional "pressure signs."

If your handloads exceed the muzzle velocity of pressure-tested loads (with the velocity and pressure taken in the same
barrel) then the pressures in your barrel are higher, even if you don't see any so-called "pressure signs," such as stiff bolt lift to ejector-slot marks on the case head.

These signs are unreliable. I have tested loads worked up with traditional pressure signs that showed no indication of high pressure, and some tested 70,000 or so in a pressure barrel."
 
coldmaker said:
loaded at 3.285” i got velocities of 3100 fps with a clean barrel at 4°c with 60gr H4831sc
and 3145 average at -8°c with a fouled barrel (after about 60 shots without cleaning)
Click to expand...

what powder charge gave you around 3040 fps? How was accuracy in the 3000-3050 fps range compared to 3150 fps 60gr?
 
3150fps is attainable with 130gr in a 24" barrel 270win without obscene pressures. After a few loadings, your brass will tell you the whole story. The previous post write up about pressures was excellent, but it appeared to be based on the assumption that the loading manuals stated velocity of 3040fps is gospel truth. A quick look at some Lee data showed 5 different powders making over 3100 fps.
 
Code: 
Cartridge          : .270 Win
Bullet             : .277, 130, Hornady SP 2730
Useable Case Capaci: 63.503 grain H2O = 4.123 cm³
Cartridge O.A.L. L6: 3.285 inch = 83.44 mm
Barrel Length      : 22.0 inch = 558.8 mm

Predicted Data for Indicated Charges of the Following Powders.
Matching Maximum Pressure: 65000 psi, or 448 MPa
or a maximum loading ratio or filling of 104 %
These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

13 loads produced a Loading Ratio below user-defined minimum of 80%. These powders have been skipped.
Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
Alliant RL26                       100.5     63.3     4.10    3240   100.0    65000   14550   0.977  !DANGEROUS LOAD-DO NOT USE!
IMR 7828ssc                        102.2     61.4     3.98    3176    96.4    65000   14284   0.969  !DANGEROUS LOAD-DO NOT USE!
AA MagPro                          103.5     64.4     4.17    3164    94.1    65000   14678   1.002  !DANGEROUS LOAD-DO NOT USE!
Alliant RL22                       103.5     61.3     3.97    3162    97.7    65000   14249   0.983  !DANGEROUS LOAD-DO NOT USE!
Alliant RL17                        91.1     55.9     3.62    3161   100.0    65000   12954   0.984  !DANGEROUS LOAD-DO NOT USE!
Ramshot Magnum                     103.3     65.9     4.27    3149    98.3    65000   13697   0.992  !DANGEROUS LOAD-DO NOT USE!
Alliant RL16                        97.2     55.4     3.59    3129   100.0    65000   12813   0.994  !DANGEROUS LOAD-DO NOT USE!
Ramshot Hunter                      95.8     57.9     3.75    3118    99.4    65000   13288   0.992  !DANGEROUS LOAD-DO NOT USE!
Alliant RL19                       100.4     58.8     3.81    3117    97.6    65000   13585   0.986  !DANGEROUS LOAD-DO NOT USE!
Hodgdon H414                        90.6     56.1     3.63    3113    98.9    65000   13314   0.993  !DANGEROUS LOAD-DO NOT USE!
Winchester 760                      90.6     56.1     3.63    3113    98.9    65000   13314   0.993  !DANGEROUS LOAD-DO NOT USE!
Alliant RL23                       104.0     59.6     3.86    3102   100.0    61498   12951   1.007  !DANGEROUS LOAD-DO NOT USE!
Hodgdon H4831sc                    101.7     60.2     3.90    3088    95.4    65000   13294   0.984  !DANGEROUS LOAD-DO NOT USE!
IMR 4831                            99.9     56.0     3.63    3080   100.0    65000   12517   1.004  !DANGEROUS LOAD-DO NOT USE!
Ramshot BigGame                     86.4     53.9     3.49    3079   100.0    65000   12201   0.999  !DANGEROUS LOAD-DO NOT USE!
IMR 4895                            86.3     50.5     3.27    3075   100.0    65000   12238   1.006  !DANGEROUS LOAD-DO NOT USE!
Hodgdon Hybrid 100V                 97.8     55.4     3.59    3066   100.0    65000   11792   0.998  !DANGEROUS LOAD-DO NOT USE!
Hodgdon H4350                       98.2     56.2     3.64    3059    98.4    65000   12627   0.995  !DANGEROUS LOAD-DO NOT USE!
IMR 4350                            96.3     56.1     3.63    3059    98.5    65000   12608   0.995  !DANGEROUS LOAD-DO NOT USE!
IMR 4320                            89.1     51.3     3.33    3057   100.0    65000   11785   0.996  !DANGEROUS LOAD-DO NOT USE!
IMR 7828                           104.0     59.2     3.83    3054    94.8    58117   13749   1.012  ! Near Maximum !
IMR 4955 Enduron                   103.0     58.7     3.80    3052    95.8    65000   12912   0.992  !DANGEROUS LOAD-DO NOT USE!
Alliant RL25                       104.0     60.6     3.92    3050    99.1    55447   13700   1.030  ! Near Maximum !
IMR 4451 Enduron                    92.6     53.6     3.47    3049    98.9    65000   12444   0.997  !DANGEROUS LOAD-DO NOT USE!
 
My go too load for hunting mule deer is 60 gr of H4831sc and 130 gr ttsx bullet at 3100 fps and that's from a 24" barrell. I haven't noticed any overpressure signs and I've been getting good case life. Next I will try RL26.
 
An old saying "if it ain't broke don't fix it".
People are shocked that I'm pushing hunting bullets out of my 300 win mag at 3330 fps with no over pressure signs.
Factors to consider are barrel throat life and barrel life. Get a cheap bore scope and watch for flame cracking at the throat. Some powders are better than others for throat longevity.
I enjoy shooting so some things will eventually wear out, including my 60 year old carcass.
 
You must log in or register to reply here.
Back
Top Bottom