Lil Gun....... AGAIN

[dale2242]

This is not a cast boolit question but......
A friend has been loading Lil Gun in a 17 Hornet.
9.8gr.----- 20 gr V max.
The load was developed in cool weather for shooting sage rats.
Pressure seemed normal with no ill effects on a sage rat shoot in cool (70-75*) weather.
Cases were reloaded and primer pockets were tight.
The next trip the air temp was hotter (90-95).
When he tried to reload them after that the primer pockets were too loose to use them.
He said he left the ammo in the sun and made no real effort to cool the barrel.
This leads me to believe that Lil Gun is quite temperature sensitive.
I have shot a 17 cal. for 40 years and am aware that small changes in 17 bores can make a BIG difference.
So what say you gents? Have any experience with Lil Gun and temperature caused pressure spikes?....dale

[dtknowles]

I shoot .22 Hornet but not 17 Hornet. The normal pressures for these cartridges are similar and lower than other modern centerfire rifle cartridges. I would take a serious over pressure to loosen the primer pockets. I have used Lil Gun in .22 Hornet on hot days (90 or greater) and not seen any pressure spikes and I have never had loose primer pockets.

More checking and more voices need to be heard.

Tim

[376Steyr]

Any rounds left from the "hot" lot? I'd pull the bullets and check the powder charges. As you said, a tiny change in powder goes a long way in the .17 Hornet. Hodgdon online data shows 9.7 grains of Lil Gun as the starting load, and 10.0 as the max. Do you know how the powder was dispensed? Sage rat shooting burns up a lot of ammo, so I'd be surprised if each charge was individually weighed.

[dale2242]

The guy is quite anal about his reloading and ,in fact, actually did weigh every charge.
I am sure there wasn`t variations in the loads.
The entire batch of brass that was shot in the heat was ruined, not just a few that might indicate varied charge weights.....dale

[ReloaderFred]

"He said he left the ammo in the sun"

This alone will raise pressures, as the heated propellant burns hotter. Leaving the rounds in the sun to heat is an old sniper's trick to get an extra few feet out of a known round at long distance.

I'm pretty sure that if he had kept his ammunition protected from direct sunlight the pressures would have been more normal.

Hope this helps.

Fred

[Tatume]

Shooting sun-baked ammunition in a hot barrel wouldn't lead me to conclude the particular powder "is quite temperature sensitive." As a shooter who often bakes in the sun myself, I put a small towel over my ammo box. It makes a big difference.

[daniel lawecki]

I shoot a 22K hornet and tried Lil Gun powder and now stay away from it. I used H110 and I have had loose pockets a well with Lil Gun and it was in the fall and they were not max loads.