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Discussion Starter #1
New toy department (not ready for primer time) :)

I am shooting 12 ga 7/8 oz loads with 17.2 of Promo, Gun Club Hulls, Fio 616 primers and CB 1100 wads. They chrono at 1250 (in summer) but apparently less when cold (30s).

These light loads work well for trap and skeet in an O/U but don't reliably cycle this gun. I want them to work even if they are slow/light. Note changing to 20.5 of Solo 1000 works it just fine.

I believe the inertia system works such that the loose bolt body bangs into the bolt spring and that in turn bounces the ass'y back into the recoil spring cycling the gun.

Bolt doesn't reliably go fully rearward to eject or pick up the next round so I suspect that the recoil spring is too strong for these loads. Are there reduced power recoil springs or should I cut coils? It gets worse as the gun gets dirty.

I know I will lose spring preload but don't think that matters.I think the in-bolt inertia spring is also ok as it simply gives back the energy going into it.

I think the main issue is cold and fiocchi and /or promo so I froze some shells and then chronod them. I found 1070 fps horrors instead of 1250. Red dot loads 17.5 did the same thing. The same loads (only 2 shells) with cheddite primers were 1 [email protected] and 1 slow at 1128 (in 1x fired GC hulls). I will try the cheddites and red dot for function and then back to the promo and see as well.

thoughts?
 

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You are trying to use the gun in a way that it wasn't designed. The inertia system was designed for loads of a minimum energy and you are below that. If you screw around with changing things you will regret it. If you want a softer shooting auto, get away from inertia cycled guns.
 

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These guns are made to cycle 1&1/8 oz. to 3' magnum loads.If you want to shoot 7/8 loads you should be shooting a 20 Ga. Mike
 

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Discussion Starter #4
Rule # 1 only screw around with replaceable parts

Rule #2 Read the manual: it says all ammunition type work without adjustment

General idea: understand how things work so you can tune them the way you want.

Like a reduced power 45 spring for wadcutters; what if no one had even tried?

I do have a 7/8s oz load that works very nicely at 1250 fps, but I don't have a lot of them ready.

The others work at first but as they chill they get marginal. I have a lot of those loaded; I think I can afford a spring eh?

I can step up the next reloads by 1/2 grain and maybe they work. If not, the o/u gets them.

Do you think the cheddite is a better cold weather primer than the Fiocchi?

thanks to those that help
 

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Benelli recommends 3 dram 1 1/8 oz. loads in all 12 gauge semi autos. Some cycles 1 oz just fine but 7/8 is pushing inertia guns to far to be reliable. Brownells sells an action spring to help cycle lighter loads.
 

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All ammunition types doesn't necessarily include reduced power hand loads. I'm a do it yourselfer too Bruce and one of the things I've learned is it's a lot easier and more expensive to screw it up than to repair it after I've applied my genius.
 

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I built an M-2 for shooting bowling pins and I wanted a lght buckshot load for less recoil. I milled weight off the bolt and shortened the spring. These are the only two ways to do it. Extreme but I can shoot 1 ounce loads through it.

CM
 

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Like said above these guns are not made to cycle those loads. Try a A300 beretta. Says it is designed to cycle 7/8 oz. Older 390's will cycle them but may need to change the gas valve spring for a lighter one which doesn't cost much.
 

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Discussion Starter #10
Velocities in cold shells were falling off, under 1100 fps and failing to cycle the gun.

Added 1/2 grain (next MEC bushing) and all is well; velocities for 20+ degree shells are all above 1125 fps and the gun cycles.

I am also using the cheddites now but even the Fiocchi 616 cycled.

No spring change

regards
 

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Bruce,

The fix is as simple as replacing the recoil spring with a replacement called "ShurCycle."

The spring in my Benelli Super BlackEagle was rusted to the point of disintegrating, so I replaced it with the stainless steel Shur-Cycle. No more worries about rust and it now will reliably cycle everything from 7/8 oz to the magnum loads. A tad pricey but worth it in the long run!

Kiv
 
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