Reducing OAL?

[kmw1954]

I just started working up a new load for a new pistol which I haven't loaded before. The Pistol is a Tanfoglio Witness 45acp. This barrel has a very tight chamber and a short leade.

So the data I'm using is from Western for Ramshot Silhouette and it recommends an OAL of 1.205" only at this length the round will not chamber well or consistently pass the plunk test. So I've now got this shortened to 1.180" and all is well with the plunk test.

Now as I've been going along I have also been reducing the powder charge to make up for the smaller powder chamber. When I got to 1.190" I reduced 0.1gr from the starting load. When I got to 1.180" I reduced another 0.1gr for a total of 0.2gr.

Does this sound about right or is it excessive? Starting load was 7.4gr and am now at 7.2gr with the length reduced .025".

[std7mag]

Kmw,

Who's bullet are you using? What weight? Lead, plated, jacketed?
How long is your barrel?

[cw308]

std7mag said it all . Safe way always is start low , I would load many rounds to start , may have feed & ejection problems from low powder charge . Doesn't seem to be a problem finding a good load . Listing for a 5" brl. with a short leade . Just work your loads up with the listed bullet for the load . Again start low an don't load alot until you find the charge that your pistol functions 100% then go for an accurate load. I would stay away from max.load listings , even though it's all steel ,why beat your pistol up.

[44 AMP]

Does this sound about right or is it excessive?

It sounds a little excessive, to me, but then, I'm a fly by the seat of your pants reloader who's been doing it for only 45 years, so don't take my opinion as gospel.

I'm glad you recognize the fact that reduction of the powder space in the case may require a reduction in the powder charge.

However, how important this is depends on many variables. The .45acp is not a high pressure "grenade in waiting" the way the .40S&W or even the 9mm Luger are. The same percentage of volume change in those rounds has a much greater effect on the pressure than it does in the .45acp.

[kmw1954]

Thanks 44 AMP, only been loading the 45acp for a couple of months and still getting a feel for it. From other loads I've worked with the Ramshot seems to be a pretty forgiving powder so yes I may have over exaggerated the reduction and a drop of just 0.1gr would have been sufficient.. Anyways, I don't have a lot of these loaded so I will try them out.

I have been loading and shooting a similar round to this one with the same powder only with a RN bullet of the same weight accept I just ran out of those. This new bullet is a 200gr Flat Point and because of the design difference I had to push it much deeper to get it to seat.

[std7mag]

KMW,

Instead of Ramshots load data, you may want to find load data from the bullet manufacturer.
Many times powder charge and COAL change.

[kmw1954]

std7mag,

Because as I keep getting reminded by all the good folks here To Quote Berry's site. Any load data will work as long as it the same weight. RIGHT!

Berry's once again does not provide load data. They tell you to go find it somewhere else!

So please explain what one is to do when one has to deviate from published data when the only published data comes from the powder manufacturer?

[Unclenick]

EDIT: I overlapped the last post and see you are using Berry's.

Ramshot's current Silhouette data is for a +P load under the Berry's 200 grain FN plated bullet. It looks like you are using that bullet. Since it is loaded right up near the top end of the +P range, you may find your caution warranted.

I don't have the length of that particular bullet, but from the photo on Berry's site estimated 0.57". QuickLOAD suggests that going from 2.05" down to 1.18, you would reduce the charge about twice as much as you did to get the same pressure. Since your exact load details are still secret, I can't claim too much for that estimate, as it is built on assumptions. Bullet construction and bullet length, as well as measured weight, could make a difference to the estimate.

[gwpercle]

You can start with the starting load. Reducing OAL by only .025" is not going to skyrocket pressure.
You are doing well to use your barrel to set OAL . Make up a few dummy rounds , no primer or powder , to test feeding. Load magazine and cycle by hand. Next , powder some up and see how they shoot.
Keep the dummies for setting dies in the future...they come in handy for this.
Gary

[Unclenick]

Gary,

QuickLOAD says the pressure increase is about 10%. The +P load is at about 22,500 psi from the Western Powder manual, and the change takes it to about 24,600 psi. Not to proof pressure, but enough to batter the gun some. Of course, this assumes the bullet is not unseated by the primer and pushed into the lands, which often happens in reality with slow powders in short powder column pistol cases, so only measurement will tell what is actually happening, and that can be a little tough to arrange on a semi-auto pistol. Scrapes the darn strain gauges right off.

Nick

[kmw1954]

Not sure where you found that Unclenick but I have the Western load data right here in front of me and I find; 45AUTO (ACP) Ramshot Silhouette, 200gr (P) BERRY FP 7.4 @ 878fps to 8.7gr @ 1034fps with a suggested OAL of 1.205", That is found on page 16. Then on page 18 I find a listing for +P Data which show Silhouette 200gr (P) BERRY FP @ 8.7gr to 9.2gr with the same OAL of 1.205"

I am certain I could have left it as-is and been safe but that wouldn't have accomplished what I was trying to do.

[Unclenick]

I must have been spinning the scroll wheel on my mouse too fast and missed that page completely. Didn't see any standard pressure Silhouette loads. But the larger change in powder charge seems to be the same at all load levels in QuickLOAD. I still don't have an accurate length number for that particular bullet, though, so there is some margin for error in the seating depth I estimated (0.288"). Seating depth is what matters to powder space and therefore to initial pressures unless you have the primer bullet unseating issue.

Seating Depth = Max Case Length + Bullet Length - COL

for 45 Auto:
Seating Depth = 0.898" + Bullet Length - COL

for 9mm Luger:
Seating Depth = 0.754 + Bullet Length - COL

For small changes in seating depth you come close to constant peak pressure by using about 0.55 times as much change in powder as in volume change. For example, your change in seating depth reduced the powder space under the bullet by 6.5% (if my bullet length estimate was right), so if you then you reduce the charge weight 3.6% (6.5%×0.55≈3.6%) you will be close to keeping the peak pressure constant. You will lose muzzle velocity because you are making a smaller total gas volume, but your peak pressure will be close to a match.

But now I know from your PM that you are looking for a mild load, I'll recommend going to a smaller charge of faster powder anyway. You'll reduce both cost and total recoil.

[kmw1954]

Thank you again kind sir!

After looking over the Ramshot load data for this bullet I see the starting point is 7.4gr of Silhouette with a Max load in the +P range all the way up to 9.2gr.. Which in my mind is a huge spread so by staying at the lower levels even a length reduction of that .025" should be more than safe.

Lastly an FYI reference on the Berry's Flat Point bullets, The 200gr has a length of .522" and the 185gr Berry's Flat Point bullet is .490"

So far I am liking this Ramshot powder and am now using it in 3 different calibers, the 45acp, 9mm and is working especially well in a 380acp load with a 100gr bullet.

Still working up developments and still looking at a couple different powders to try such as AA#2 and Ramshot Competition as I've seen some interesting loads for the 3 guns I shoot.