Spray back from moderator

[squatman86]

Hi there,

I'm using a Tikka T3 .308 Varmint with a Riflecraft Hardy GEN IV Moderator.

When firing with the moderator on I get a blast of air back at me the shooter sometimes with bits fired back at me, this is also making a mess of my scope.

Is this normal? I'm target shooting so perhaps shooting off more than if I was stalking, so I need to clean the mod and/or barrel exterior between a certain amount of shots? Or is there something wrong here?

Any thoughts, advice or suggestions would be appreciated.

Thank you.

[Mauserbill]

Hello
Are you using Factory ammunition, home loads, or perhaps downloads ?

[Alpha1]

How old is the moderator sounds like it may be blocking up might need dismantling and the carbon cleaning out.

[Otley]

Are you sure the blow back isn't coming from the breech? Cartridge fires, case obturates, pressure drops and case contracts but the bullet hasn't yet cleared the moderator, so gas can now escape rearwards past the contracted case and out of the breech vent holes. Difficult to see how propellant gasses can exit the muzzle and do a 180 degree turn to come back to the shooter. I assume the moderator is fully screwed home and there's no gas path from the back of the moderator?

[squatman86]

Thanks for your replies.

@Mauserbill - Factory

@Alpha1 - please see attached image, not sure it can be dismantled, unless there is a specialist tool to screw into the end and pull it apart somehow. I have done my best to clean it out with action blaster and napier rapid degreaser.

@Otley - Blow back is definitely from mod as can see bits on top of barrel, and as I mentioned it makes a mess of my scope (objective lens). Mod is tightly screwed, but I'm not the condition of the moderator thread as difficult to inspect in my unit, the end of my barrel (before thread) has some pitting, but the thread of the barrel and moderator should create the "seal" shouldn't it?

Thanks again all.

[dromia]

Have you checked for cross threading?

[squatman86]

@Alpha1 - I forgot to state I've had the moderator almost 5 years, bought it used with the rifle. May have been under a year old when I bought it.

@dromia - as far as I can tell there is no cross threading, that being said there is a bit of sharpness to some areas of the thread that get a bit caught on my rag when cleaning. I've attached best photo I can get down the moderator.

Thanks again for your replies.

[dromia]

What are the muzzle threads like?

[ovenpaa]

A rear bush would help a bit but not completely. The issue is usually because the rear is open to the front section.

[meles meles]

* phew *

We saw the title and thinked it meant Dromia had pi**ed on you. Thank 'eavens not.