Scale Gun Barrel Sizing Chart
For Hypodermic Tubing
1/72 Scale
Caliber I.D. Tubing Gauge + Tubing O.D. Part # -304 * Part # - 316 *
.30 cal. ** 0.00416 33 0.008 HTX-33R N/A
.50 cal. *** 0.00694 28 0.014 HTX-28R HTXX-28R
20mm 0.0109 25 0.02 HTX-25R HTXX-25R
25mm 0.0131 23 0.025 HTX-23R HTXX-23R
30mm 0.0164 22 0.028 HTX-22R HTXX-22R
1/48 Scale
Caliber I.D. Tubing Gauge + Tubing O.D. Part # -304 * Part # - 316 *
.30 cal. ** 0.00625 30 0.012 HTX-30R HTXX-30R
.50 cal. *** 0.0104 25 0.02 HTX-25R HTXX-25R
20mm 0.0164 22 0.028 HTX-22R HTXX-22R
25mm 0.0205 21 0.032 HTX-21R HTXX-21R
30mm 0.0246 20 0.0355 HTX-20R HTXX-20R
1/32 Scale
Caliber I.D. Tubing Gauge + Tubing O.D. Part # -304 * Part # - 316 *
.30 cal. ** 0.009375 26 0.018 HTX-26R HTXX-26R
.50 cal. *** 0.015625 22 0.028 HTX-22R HTXX-22R
20mm 0.0246 20 0.0355 HTX-20R HTXX-20R
25mm 0.03075 19 0.042 HTX-19R HTXX-19R
30mm 0.0369 18 0.05 HTX-18R HTXX-18R
1/24 Scale
Caliber I.D. Tubing Gauge + Tubing O.D. Part # -304 * Part # - 316 *
.30 cal. ** 0.0125 24 0.022 HTX-24T HTXX-24T
.50 cal. *** 0.02083 21 0.032 HTX-21R HTXX-21R
20mm 0.0328 18 0.05 HTX-18R HTXX-18R
25mm 0.041 17 0.058 HTX-17R HTXX-17R
30mm 0.0492 16 0.065 HTX-16R HTXX-16R
1/35 Scale
Caliber I.D. Tubing Gauge + Tubing O.D. Part # -304 * Part # - 316 *
.30 cal. ** 0.00857 27 0.016 HTX-27R HTXX-27R
.50 cal. *** 0.0143 24 0.022 HTX-24T HTXX-24T
20mm 0.0225 20 0.0355 HTX-20R HTXX-20R
25mm 0.0281 19 0.042 HTX-19R HTXX-19R
30mm 0.0337 18 0.05 HTX-18R HTXX-18R
(+) The gauge has been rounded out to the closest available from
www.smallparts.com
(*) These are two different grades of hypodermic tubing
(**) Can be used for 303 British, .30 cal. Browning, 7.62 x 39mm, 7.62 x 51mm, 7.7
Japanese or Arisaka
(***) Can be used for .50 cal. Browning or 12.7mm Russian