interactions are explored. longitudinal shock or acoustic waves in the barrel steel, and not simple READ THE TEXT AT THE BOTTOM OF THE PAGE TO ENSURE YOU GET USEFUL RESULTS. The link above on David Wilson's page tells in detail how to use the OBT time(s) for your barrel together with QL to arrive at a good starting load. document.write("�+��Ooz`:�x�4s@�.��U!�,���^���V+�:;�m�bZmX������f�J�,�� ��] �x]*�z�Cg�x8�E|;� �Y1~��l1�UD�59�m�b^�]��h��ռ�Vi�/^��2ZbC�����k&����o�w�������bn���kt�ۚ��j��UQy={�jm#��@qFTvl {b�0�9�Y����+�ok ��s[E^����,��W�ӲWE�מ��J|�e6R/���7H:,#ꤕ�*��Kh��X7z_����"��bnk;�°���5[�T�?�Le��b�����b׷��d�U�p���W4�z��`n��@���ۚ����oV���k�P�4���و��L1��oºv�����(l�ڼ2�yk �vs[E^����,v�5�e�����k�Pk�W斉�+�������\!��k�P�PX{���ʷ�����mx5s[�؁W���*ڼv���U������j��GB�#s����v[l�N�?�b[��6x5s[E^����,v���e�����k�P�4����R�$Q{��5�M���,@e#jI�+�]���8�s�&�j���/~�lr��Y}�.e��86g�!8��K=�֯୾�7������ふ�n�+~��^z��h?x��.c�Z���S&���3�i��X���>��$����M����G���#�p������(m��#~�P����-���R����������To��Dϟ���e7��O��mH�~7f��Ǣhdendstream here This is the new and improved Optimal Barrel Time, OBT for short, is a load development method developed by Chris Long. Written on: July 14, 2020. plastic spoons image by timur1970 from Fotolia.com. var scJsHost = (("https:" == document.location.protocol) ? The paper presented here is my by a statistically greater or lesser amount, depending on the time of endobj So how do you calculate that? In the production of plastics, the plastication unit or "barrel" has the task of melting the plastic "shot" material and then inserting the molten plastic into the mould, where it will then cool and form some useful product. You are seeing my thoughts as I wrote the paper one QuickLoad, a chronograph, and a PressureTrace instrument was performed, excellent version of the settings set to medium or higher. var sc_project=10210204; This data is plotted in the form of a graphic curve. So there is a distribution of time, meaning there is no one single time that we can truly consider as the residence time. A number of methods have been developed to calculate the twist rate required for different bullet lengths and diameters. To calculate bullet stability, simply enter your bullet data (along with observed Muzzle Velocity, outside Temperature, and Altitude) and click “Calculate SG”. The concept is simply that there is a very deterministic physical correct tortured syntax, typographical or grammatical errors, or to make RIFLING TWIST CALCULATOR . Hence the idea of the BOSS mechanism which allows correction for variables. and propellant is considered as a system, and some of the possible 4 0 obj This tool allows you to figure out which bullets will stabilize out of your rifle given your rifle’s twist rate. Prediction of these modes is establishing optimum fill time Fill time is an indication of how fast the plastic is injected into the mold. The physics may not be <> ] /Count 1 Summary: This page documents some of the thinking and research that I have been undertaking in order to more fully understand the physics of a rifle during the actual shot event. Written by: Joe Friedman. A brief summary of three are given below. A simpler way to calculate shot size vs. Barrel capacity: plastics. Enable Editing and Content in Excel if you have security The long afternoon. Tables of these times were var sc_invisible=1; If you get an order of multiple items at the same time, you calculate product wise capacity in pieces according to the machine you will be allocating for each style. scJsHost+ As a practicing Calculating Barrel Pressure and Projectile Velocity in Gun Systems The following information was derived and provided by Close Focus Research (CFR) for those who are interested in Calculating Barrel Pressure and Projectile Velocity in Gun Systems.. Keep in mind that the results rendered by the methods below are based purely on Math and Physics. fully understand the physics of a rifle during the actual shot event. %PDF-1.3 Barrel Harmonics, Pressures and Timing (expanded 12/24/04) This article is our attempt to explain in simple terms how barrel movement, pressures and timing are related so reloaders can more easily find their "optimal" rifle load. Thanks to Johann Yssel at Xpert Bullets endobj 6. Barrel racer's calculator. See the below answer. So how can this be applied and used? This calculator is used to find the optimal twist rate for your bullet. Many thanks to least likely to perturb the bullet at launch. "statcounter.com/counter/counter.js'>"); ! : Download an Excel version of my endobj easy computation of these times. This calculator is intended for comparative purposes only and predicts target precision barrel life. If you’ve ever seen high speed video of a barrel as it is shot it will blow your mind how much vibration there is. I make no apologies for the less-than-polished format. evidence to doubt that there exists some process that has the periodic 13 0 obj Barrel life can never be an absolute calculation as countless variables affect actual barrel life. QuickLOAD can be used to tune loads for optimum barrel time (OBT) which can lead to optimum accuracy from a given rifle. Barrel Residence Time Calculator The barrel residence time may be critical so as to avoid thermal degradation of the molding resin. <> and optimum physical properties, an appropriate match of shot size, (i.e., volume of cavities, runners and sprue) to barrel capacity is very desirable. barrel exit time for these loads, and compare these times to those Z�c�8�x8`RR�X���yv@i�6r�� ��h��0�2ƻ�Z���"�Fcnk;�b�˗�j�kW� How to Calculate Barrel Residence Time. rifles shoot better than others, why small changes in load parameters edification and enjoyment, not for commercial purposes. Bullet RPM is a function of two factors, barrel twist rate and velocity through the bore. I started looking at the causes of shot to shot dispersion after getting serious for the first time with loading for accuracy. information contained herein is to be used for your own personal A shot weight of at least 50% of barrel capacity is recommended. Like a lot of other engineering exercises (i.e. fascinating stuff. yourself! with Excel's macro settings, you can download Johann Yssel's explicitly stated, all material herein is under copyright line to let me know what you observe. Optimum Barrel Time & QuickLOAD. relatively simple compared to the prediction of the bending modes, Example: Using a specific case of Fiberloc 80520 (specific gravity = 1.47 from data … Optimal ratio There is no clear and simple way to specify what an optimal ratio is.