New low brass Fiocchi 2 3/4 20 ga hull problems, Ideas??

[P.coverts]

So patterned some Duplex Tss, steel hand loads 1 oz 20 Ga in the 1500 fps variety and it appears that something is going wrong the patterns with Light Mod out of my Beretta A400 20 Ga 3" at 30 yards are fantastic (in my book) in the mid to high 70% range in a 30" circle (honestly better than any 12 ga factory steel load I have ever patterned so I am very pumped). The problem is the first shell will eject and the bolt will not hold back, if I try 2 shells the second shell will not load. I shot Kent steel dove loads steel 7/8 at 1400 FPS at doves no problems, Boss 3" 1400-ish flavor Bismuth no problems tried a few things and still a no go for cycling with my new Fiocchi 2 3/4 roll crimps hulls.

The New Fiocchi hulls are low brass, it appears the brass/steel is so tight after one is shot there is not enough energy to eject and reload it or hold back the bolt. I put a spent hull in the chamber and slam it home it is so tight it is very hard to get it out the bolt is almost stuck so it seems like some swelling of the brass. A new unfired hull fits and ejects but they are tighter than any other hull I have tried. I have some loads of a different flavor getting tested this week at precision same hulls and they are aware of the issue.

Anyone have this happen or any suggestions I am really pumped on the patterns but a single shot is not what I am going for.
Ideas I have thought of.
1. I have thought of and not tried backing off the powder 2-4 grains thus going 1400-1450 range.
2. Using a high brass hull.
3 Quit hunting

Thanks
PC

[bullet225ho]

So this is only happening on the new fiocchi hulls? what is the brass length or height of these hulls?

[Greg]

I am using the high brass hulls and the cycle fine in an 1187. If you want to try a couple shoot me your address in a message and I'll send you a few.

[P.coverts]

New 8mm hulls, Im going to call ballistic products today about a return seeing I have 300 of these hulls I was thinking about the high brass. Bummer is I have a dozen of these reloaded taking them apart is harder than reloading them
Im going to see what my options are with BP.

Greg I appreciate the offer I might take you up on that.

[continental shooter]

hey,

care to share the full load? it might just be the pressure bulging up the head and making it too tight for the extractor to pull.

I only use Fiocchi hulls and mostly 8mm head (T1) but not encountered the same issue so far; although I only shot 3 last Saturday.

The issue i found was with the 3" one and RTO getting stuck and not chambering right; however, when i measured the total height for the crimped hull it is within standard.

Cheers,

[Dave in AZ]

Hey, unless youre going to measure the diam of the hulls before and after firing, and post the numbers, it's all opinion...
The first thing to do is measure diam.
Next, is this only happening w roll crimps? Italian guns, spec franchi, don't make the bolt cycle long enough to do a full length saami compliant roll crimp. See dla blog for research and info on this.
Next, is your load pressure tested, or assumed pressure from some other load, and what is tba5t pressure.

Last, did you try resizing the unfired shells down to well below saami chamber spec? The inelastic expansion of their steel heads means they get stuck in lots of guns... many.including myself cant shoot steel head fed or fiocchi ammo in tight tolerance chambers. Overly resize it down .05 more, see how that helps deal with the head expansion, if this part ends up your prob.

[P.coverts]

It looks like a pressure problem, my test shells came back way high, this was from a tested load so there is a problem somewhere and precision is helping me get to the bottom of it. My shotgun is a400 is a 3 " gun so I think the 2 3/4 hull should work but the pressures were very high. My gun runs 3" boss bismuth perfectly and 2 3/4 Kent dove steel at 1400FPS no problems. The hulls are expanding brass is .070 at the base and .069 at the top after firing. Just need to get the new loads tested this week and see where I am at on them. sent in 3 strings to be tested. so I am doing my due diligence. Precision reloading has ben very helpful and are great to work with and recognize there is a problem somewhere. I have double checked everything, looks like I need to drop down on powder for sure and did on one of the first tested strings and the pressure was still way to high.

[P.coverts]

BTW new hulls .06910 .06920 at base and .069 at top so it looks like the base is expanding.

[continental shooter]

Sorry,

I had a link to it but it's no longer working

What are the saami compliant length for roll crimp and fold?

Back when my grandpa had his gunshop all his laods were roll crimped and none of his customer ever had a problem with cycling (being Italian all guns were pretty much Italian).

The other thing to watch out for is closure height; in a normal lead shell pressure jumps ~1500 psi per mm

the established height to close (RTO) 70 mm hulls is 65 mm and 64.5 being the exception (very slow powder with light loads) or for EU stile star crimp is 60 (exceptionally 59.5). So, if you close 1-1.5 mm shorter than standard/required height chances are you bumped pressure enough that the tiny brass was not able to handle it (compared to the higher one).

Also, not knowing the load or whether any other components has been changed (Wad and primer would be my first suspects) it's hard to say.

Cheers,

[P.coverts]

All my test loads with lil Gun have come back with high pressures (all 5 strings of 6 shells), even with backing down to 34grains, just not having any luck. It looks like the high pressure is the culprit and the pressures were all over the place some very high working on some other solutions, and possibly scraping lil gun altogether. Lil gun is just not working for my loads or for test loads done by someone else.