Shotgun Bandit Posted January 29, 2011 Posted January 29, 2011 OK here goes. I'm loading 38 ...90 grain boolits ..... Boolit A is 358 diam chronos at 650 fps Boolit B is 359 diam chronos at 475 fps Same powder......Same powder charge....Same press....Same crimp....... Same Gun........Shot on the same day with the same Chrono. So my Question is........WHY ?????..........................................Thanks Bandit
Gold Canyon Kid #43974 Posted January 29, 2011 Posted January 29, 2011 OK here goes. I'm loading 38 ...90 grain boolits ..... Boolit A is 358 diam chronos at 650 fps Boolit B is 359 diam chronos at 475 fps Same powder......Same powder charge....Same press....Same crimp....... Same Gun........Shot on the same day with the same Chrono. So my Question is........WHY ?????..........................................Thanks Bandit Neither makes the SASS power factor of 60.
PaleWolf Brunelle, #2495L Posted January 29, 2011 Posted January 29, 2011 OK here goes. I'm loading 38 ...90 grain boolits ..... Boolit A is 358 diam chronos at 650 fps Boolit B is 359 diam chronos at 475 fps Same powder......Same powder charge....Same press....Same crimp....... Same Gun........Shot on the same day with the same Chrono. So my Question is........WHY ?????.......................................... Ain't it obvious?...the larger diameter bullet encounters more drag resistance in the rifling (tighter fit) which causes it to slow down before exiting the barrel.
Shotgun Bandit Posted January 29, 2011 Author Posted January 29, 2011 GC.....The reason I was testing was to see what the PF was........Since it is obvious they don't make it......The Question still remains WHY......Bandit
Tye Riverman, SASS #41433 Posted January 29, 2011 Posted January 29, 2011 Very light loads with light bullets give inconsistant velocities, it appears you need to bump up your powder charge. YMMV Tye
Widder, SASS #59054 Posted January 29, 2011 Posted January 29, 2011 Zackly what PWB sed. If you were shooting it in a rifle, that would make alot of sense to me. If you were shooting it in a pistol, I would think the velocities would not be as great a difference. PLUS: if your using a fast burning powder, somewhere during the short time frame that the bullet is still in the barrel, all your powder has burnt and the 'push' of the expanding gases has started to deminish therefore the tightness of your bullet is causing greater drag. Course, I could be wrong. I ain't slept in a Holiday Inn in a loooooong time. ..........Widder
Shotgun Bandit Posted January 29, 2011 Author Posted January 29, 2011 P W and Widder...........Thanks..........I wuz thinkin that the larger boolit would cause more pressure to build and it would be faster. Thanks again .........Bandit (who is feelin dumber than usual)
twelve mile REB Posted January 29, 2011 Posted January 29, 2011 Serveral things COULD BE happening. 1. The bullets could have been cast from different alloys. Using Very hard to very soft bullets have produced some interesting variaion in velocites for me. 2. If this is a light load and it looks to be, powder posistion within the case can and has for me caused variation in velocities. 3. Using regular primers rather than Mag primers with a light powder charge can cause incomplete combustion and therefore lower velocities than expected. 4. The larger bullet just hates being resized and leads the crap out of your forcing cone, barrel. 5. A little bit of all of these. 6. I'm totally wrong and its none of these. 12
J-BAR #18287 Posted January 29, 2011 Posted January 29, 2011 Just one more example of ballistic results that are counter-intuitive and illogical. Just one more example of why we should respect the loading chart's minimum and maximum load data, and not go to extremes outside those limits.
Big Jake1001 Posted January 29, 2011 Posted January 29, 2011 At those velocities, you'd be better off throwing big rocks at the target. Just saying Big Jake
Assassin Posted January 30, 2011 Posted January 30, 2011 SB, Were you using all the same cases. Nickle will not give you the same velocity as brass cases. Nickle does not expand at lower pressures. And, some brass has different case thickness and will expand differently at lower pressures. Did you only use two rounds in your chrono test. IMHO these loads are way underpowered and you are setting yourself up for problems. When testing use the same brand of brass for each load, each round also needs to be the same temperature. I'd load at least 5 of each. LL'
Tuco Forsyth #72674 Posted January 30, 2011 Posted January 30, 2011 Shoot black powder and not worry about things trivial.
Oklahoma Dee Posted January 30, 2011 Posted January 30, 2011 Hey Shotgun Bandit! Sunday Morning and the coffee is good and its drizzlin rain here in Houston, Texas - Couple of common items, Based on velocities, your shooting a pistol. ( I Hope) I load 90gr bullets in my Colts/USFA's, type of powder and primers play major roles. The bullet,regardless of diameter... not so much. Although, I use the .359 most of the time. Brass has to be consistent, cracks even little ones around the lip can really release pressure and you will get low readings, which are correct (usually). Do not use beatup, discolored brass. Look at the brass after you have fired 5 rounds through the chronograph, - any with powder left in them? sides scorched? any with split lips? Primer looks flat or kinda pushed in? What kind of gun are you shooting? Older guns can have one or more cylinders holes out of specs. This can cause the brass not to expand to the confines of the cylinder and lowers the reading, which is correct. All in all, you now have a base on which to build from. You found out that your gun shoots inconsistent velocities with this load. Review your information and maybe all you need is Magnum primers( I am convinced that they are the best ) . Maybe a bump up of half a grain. Maybe a change of powder. Your in control. If you need some loading info PM me and we can exchange thoughts. Great luck and be safe. Oklahoma Dee
Throckmorton,23149 Posted January 30, 2011 Posted January 30, 2011 The powder residue from the 1st wimp loads is fouling the barrel so badly that the second round of wimp loads cant fight their way outta the crud in the barrel. Load 'em up and let em fly,RING that steel,let em know ya ain[t a feard a no recoil no how !
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