1. Attention: We have put together a thread with tips and a tutorial video to help with using the new software. Please take a moment to check out the thread here: Trapshooters.com Tutorial & Help Video.
    Dismiss Notice

How much pressure to cycle a 391

Discussion in 'Shooting Related Threads' started by amboy49, Feb 19, 2011.

Thread Status:
Not open for further replies.
  1. amboy49

    amboy49 Well-Known Member

    Joined:
    Jul 23, 2007
    Messages:
    1,162
    Location:
    out in left field
    I've been loading some shells with 7/8th oz shot for softer recoil and they won't eject. Recipe is: Win AA hull, 16.5 grains of Clays, grey Claybuster wad, Win 209 primer. A friend informs me the Clays powder doesn't generate enough "gas" to make my Beretta 391 cycle properly. I believe published data indicates this load will generate 1150 fps with 7400 lup. Gun is fitted with a 28" barrel that is ported.


    Is there a different powder I could/should be using that I can still load with 7/8 oz load and generate enough pressure to cycle the gun ?


    Thanks in advance
     
  2. 391 SL

    391 SL Member

    Joined:
    Jan 29, 1998
    Messages:
    32
    Is the grey wad the replacement for the AA12L? Check out the website, it looks like you need some more powder. My 391 will cycle pretty much any 7/8 oz load going 1200 fps or faster.

    http://data.hodgdon.com/shotshell_load.asp
     
  3. Dickgshot

    Dickgshot Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    3,676
    Your 391 can cycle just about anything, you just need to put a stronger spring in the gas valve. Cole's sells a set of two replacement springs -one stronger and one weaker to regulate the gas valve. You can also put in a couple washer
    behind the gas valve spring which will help prevent the gas valve from opening too much.
    What the stronger spring does is prevent gas from bypassing the piston - thereby applying more force to the bolt.
     
  4. jimrich60

    jimrich60 Member

    Joined:
    Aug 15, 2007
    Messages:
    810
    As dickgtax notes, many/most 391s do not work well with the very light loads, like the 7/8 oz loads at 1200 fps or less. Changing powders will not help here (although faster 7/8 oz loads will work if they are up around 1300-1350 fps). Light loads simply do not generate enough gas pressure to reliably operate the system with the standard factory gas spring. As noted, the solution is simple. Get a set of the Cole springs and install the heavier spring for the lighter loads. This will hold the gas valve closed for a longer period of time, thus allowing the lighter loads to operate the bolt properly. The heavier spring will also work ok with slightly heavier loads,such as 1oz and 1 1/8 oz loads up to about 1200 fps. Just don't use it with heavy field loads, or the 3 inch loads. For those, go back to the factory spring, or even the lightest Cole spring. Only takes a couple of minutes to change springs, so not really an issue and Cole colors the springs different colors so you can readily tell which one you are using. They have worked great in my 391, and allowed me to use light 7/8 oz loads reliably.

    Jim R
     
  5. Joe O

    Joe O Member

    Joined:
    Jan 29, 1998
    Messages:
    319
    Location:
    Minnesota
    I have even been able to get the red spring to work with 3/4 oz loads. This is the ultimate training load and what I use to start beginners. After about a box or so of these you can go up to 7/8oz loads and they don't even notice. those first shots are SO important with beginners.
    I find the blue spring softens the recoil sensation by slowing the bolt, try it you may like it. My empties come out like you have a deflector on the gun. You do have to be a liitle more carefull about how dirty you let it get.
    Joe O
     
  6. amboy49

    amboy49 Well-Known Member

    Joined:
    Jul 23, 2007
    Messages:
    1,162
    Location:
    out in left field
    I was going to take the advice of dickgtax and order the two spring set from Coles for my 391 to get it to eject light load shells. The $16.00 seems a little pricy, but something I could live with. Then I checked shipping charges - $12.60 for UPS ground to me in Indiana ! ! ! ! I'm figuring they're going to throw the springs in bubble bag and it will cost them less than $5.00 to ship. Should I contact them to advise they can ship in a USPS box for $5.00 ? ( At least according to the USPS television commercials ). If I wanted the part next day air the shipping charge identified was over $95 ! ! Must have a helluva shipping department (perhaps union ) or the package comes lined in gold. I think I should throw a couple of washers under the spring as suggested and see what happens.

    I also thought about purchasing the socket that is used to take of the retaining nut of the gas valve spring until I saw they wanted $34.95 for just the socket itself ! I was afraid to check shipping costs.

    So, anyone got an extra set of springs and/or the socket they're not using anymore ?

    thanks
     
  7. Dickgshot

    Dickgshot Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    3,676
    You might try the washer alternative. Go to your local hardware store and see if you can find metal washers with something close to a 3/4" OD , and a 1/2" or greater ID. Get them somewhere between 1/16" and 1/8" in thickness, and get several. Add or subtract the washers at the end of the spring, until you get the bolt to cycle the way you want. The whole thing should cost a couple dollars at the most.
     
  8. cbxchris

    cbxchris Active Member

    Joined:
    Jan 10, 2006
    Messages:
    771
    I use 17.3 grs of promo and 3/4oz and NEVER have a issue with cycling. Just shot a round of skeet today with that very load.
     
  9. straightsixes

    straightsixes TS Member

    Joined:
    Jan 21, 2007
    Messages:
    51
    Bingo on the 17.3-17.5 promo and 3/4 oz loads. I tried the same thing for my daughter's 3901 RL and it worked great. Tried them in my 391's (main and backup guns) and they work amazingly well.

    Actually went all the way down to 5/8 oz loads which worked the first few days after loading them, but then started to "dud" out after sitting a while (room in the wad... so it makes sense that pressure issues surfaced. Again, I was completely shocked that the freshly made 5/8 oz loads cycled perfectly as we shot pairs together. Talk about hearing the action... good grief all I heard was the crunching of the action, as the regular shell firing noise was greatly reduced.

    This was with standard factory springs on all 3 Berettas.
     
  10. Shady Creek

    Shady Creek TS Member

    Joined:
    Feb 5, 2006
    Messages:
    573
    Get the heavy spring from Cole, the washer works on a 390, 391s are different. That load works in my 391 Mobile Choke Barrel when it's clean. I've seen other 391s that wouldn't cycle that load...........GOOD LUCK
     
  11. amboy49

    amboy49 Well-Known Member

    Joined:
    Jul 23, 2007
    Messages:
    1,162
    Location:
    out in left field
    I may try the washer trick and see how that goes. The barrel I'm using, which was purchased used, is a 28" mobile choked barrel AND is ported. I'm actually wondering if the barrel being ported has any affect on the resistance of the gas pressure ?

    I have a 32" barrel and think I'll throw that on the gun to see if there is any difference in the function.

    I had planned to use up the rest of a 4# keg of Clays before opening the jug of Promo that I have - sounds like I should give the Promo a try.

    I'm sure folks are successfull in getting these guns to function reliably since so many are shot on the sporting clays and skeet ranges. I'll give it another good cleaning, load up some Promo loads, and see what happens.

    Anyone got the "specialty" socket for less than $33 plus shipping ?
     
  12. shotgun 1

    shotgun 1 Member

    Joined:
    Aug 25, 2006
    Messages:
    233
    I got a 391 barrel ported years ago and it would no longer cycle with the loads I had been using. I've shot 28" Mobil choked barrels for years and would have no hesitancy using the load you describe. I've never been able to rationalize the effect that porting had,since it seems the gas would bleed into the ports before any reduction caused by porting would have an effect. Sold the gun to a "friend" on payments and never did get any more after the first payment. If he still has it, I hope it still malfunctions.
    Dave
     
Thread Status:
Not open for further replies.