Caused by 0: java.lang.NoClassDefFoundError: com/mrcrayfish/guns/network/message/MessageUpdateGuns
at java.lang.Class.getDeclaredMethods0(Native Method) ~[?:?] {}
at java.lang.Class.privateGetDeclaredMethods(Class.java:3458) ~[?:?] {}
at java.lang.Class.privateGetPublicMethods(Class.java:3483) ~[?:?] {}
at java.lang.Class.getMethods(Class.java:2068) ~[?:?] {}
at net.minecraftforge.eventbus.EventBus.registerClass(EventBus.java:83) ~[eventbus-6.0.3.jar%23128!/:?] {}
at net.minecraftforge.eventbus.EventBus.register(EventBus.java:126) ~[eventbus-6.0.3.jar%23128!/:?] {}
at net.minecraftforge.fml.javafmlmod.AutomaticEventSubscriber.lambda$inject$6(AutomaticEventSubscriber.java:61) ~[javafmllanguage-1.19.2-43.2.3.jar%23153!/:?] {}
at java.util.ArrayList.forEach(ArrayList.java:1511) ~[?:?] {}
at net.minecraftforge.fml.javafmlmod.AutomaticEventSubscriber.inject(AutomaticEventSubscriber.java:48) ~[javafmllanguage-1.19.2-43.2.3.jar%23153!/:?] {}
at net.minecraftforge.fml.javafmlmod.FMLModContainer.constructMod(FMLModContainer.java:78) ~[javafmllanguage-1.19.2-43.2.3.jar%23153!/:?] {}
at net.minecraftforge.fml.ModContainer.lambda$buildTransitionHandler$10(ModContainer.java:121) ~[fmlcore-1.19.2-43.2.3.jar%23152!/:?] {}
at java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1804) ~[?:?] {}
at java.util.concurrent.CompletableFuture$AsyncRun.exec(CompletableFuture.java:1796) ~[?:?] {}
at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:387) ~[?:?] {}
at java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1311) ~[?:?] {}
at java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1840) ~[?:?] {}
at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1806) ~[?:?] {}
at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:177) ~[?:?] {}

0.2 version has solved the problem.