Cyclotol is an explosive consisting of castable mixtures of RDX and TNT.

It is related to the more common Composition B

Composition B

Composition B, colloquially "comp B", is an explosive consisting of castable mixtures of RDX and TNT. It is used as the main explosive filling in artillery projectiles, rockets, land mines, hand grenades, sticky bombs and various other munitions...

, which is roughly 60% RDX and 40% TNT; various compositions of Cyclotol contain from 65% to 80% RDX.

Typical ranges are from 60/40 to 80/20 RDX/TNT, with the most common being 70/30, while the military mostly uses 77/23 optimized in warheads.

Use

Cyclotol is not commonly used, but was reportedly the main explosive used in at least some models of US Nuclear weapon

Nuclear weapon

A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

. Sublette lists Cyclotol as the explosive in the US B28 nuclear bomb

B28 nuclear bomb

The B28, originally Mark 28, was a thermonuclear bomb carried by U.S. tactical fighter bombers and bomber aircraft. From 1962 to 1972 under the NATO nuclear weapons sharing program, American B28s also equipped six Europe-based Canadian CF-104 squadrons known as the RCAF Nuclear Strike Force...

 and possibly related weapons that used the common Python primary

Python primary

According to researcher Chuck Hansen, the W34 Python was a gas-boosted fission primary used in several designs of American thermonuclear weapons....

 - W34, W28, W40

W40

The W40 nuclear warhead was an American nuclear warhead developed in the late 1950s and which saw service from 1959 to 1972. It was a fusion boosted fission bomb type....

, and W49

W49

The W49 was an American thermonuclear warhead, used on the Thor, Atlas, Jupiter, and Titan I ballistic missile systems. W49 warheads were manufactured starting in 1958 and were in service until 1963, with a few warheads being retained until 1975....

.

It was also used in the B53 nuclear bomb

B53 nuclear bomb

The Mk/B53 was a high-yield bunker buster thermonuclear weapon developed by the United States during the Cold War. Deployed on Strategic Air Command bombers, the B53, with a yield of , was the most powerful weapon in the U.S...

and associated W53 warhead.