PolarStar has been naming their nozzles with numbers instead of gun models since July 2016. This is because the nozzle length can vary between the same gun model when it is made by different manufacturers. The reason for this is the small dimensional differences in the parts used by different manufacturers, and even the thickness of the gear case shell can vary between different manufacturers. For example, a standard MP5 can require any of four different nozzle lengths depending on the manufacturer.
PolarStar maintains an extensive nozzle compatibility chart on their website Help Center page. Check out the compatibility chart here.
Once you have determined which nozzle number fits your airsoft gun, that number is universal across all PolarStar HPA units that use a numbered nozzle system (with the exception of some model specific Kythera systems). So if you determine that your airsoft gun requires nozzle number #11, you should install the nozzle number #11 whether you install a Jack, Kythera or F2 unit.
If your gun is not listed in the PolarStar compatibility database, the recommended nozzle length can be calculated by measuring the gun's gear box shells and the original nozzle with a caliper. The correct nozzle length is obtained by using the caliper measurements and the formula below. Please note that measurements must be made in thousandths of an inch (0.001").
F2 Centerline Nozzles:
TIP (TIP LENGTH )= F + B - (A/2) + 0.293
(More accurate measurements can be obtained by installing a nozzle in a system that is slightly too long for the replica and measuring the nozzle's fit into the hop-up chamber.) The measured tip length should be +/- 0.010 inches compatible with the existing nozzle. If the tip length you measured does not match the production nozzle within +/- 0.010 inches, the nozzle is not currently manufactured for that rifle. If a suitable nozzle is not available, please contact our customer service department and we can order a custom nozzle from the manufacturer.
| Num |
Most Commonly Used With |
Tip |
| 1 |
TM M4/M16, A&K PKM, TM MP5 A/SD, ICS MP5 A/SD, G&G KAC SR-25E2 |
1.205 |
| 2 |
CYMA AK, CYMA MP5 A/SD, G&G UMP |
1,242 |
| 3 |
CA M249/MK46, A&K M249/MK46 |
1.19 |
| 4 |
G&G GR-25 |
1.8305 |
| 5 |
A&K SR-25, JG SR-25, ICS SIG 550/551/552 |
1.3435 |
| 6 |
KA FAL, TM MP5K, A&K M240 |
1.2745 |
| 7 |
PTS MASADA, CA SCAR-L |
1,514 |
| 8 |
VFC SCAR-H |
1.8875 |
| 9 |
EF/S&T TAR-21 COMP |
1.2565 |
| 10 |
EF ARX160 ELITE |
1,866 |
| 11 |
CA KAC LMG, VFC MP5 A/SD |
1.127 |
| 12 |
LCT AK-47/74/M |
1.2155 |
| 13 |
A&K MASADA/ACR |
1.7265 |
| 14 |
KA CZ 805 BREN, CG M249 FEATHERWEIGHT, A&K M60 |
1,769 |
| 15 |
EF/ARES G36KV/CV, JG G36 |
1,434 |
| 16 |
EF/S&T G36C |
1,421 |
| 17 |
CA AUG |
1,384 |
| 18 |
G&G MP5 A/SD |
1.175 |
| 19 |
VFC/ECHO1 XCR |
1.6065 |
| 20 |
CA G36, CYMA SR-25 |
1,406 |
| 21 |
Elite Force/CYMA MP5K, CA SA58 |
1.303 |
