Determining OAL for a pistol?

[Lojak]

Hi all,

Perhaps I've put on the stupid hat today, but I'm trying to figure out the best way to test if rounds will chamber properly. Based on what I've read, a lot of folks will remove the barrel from a pistol and drop in rounds to verify correct seating.

In my situation, I have a pistol with a tight chamber, and if rounds will actually chamber properly before I'm at the range, and otherwise subjected to many frustrating FTF's.

So, how should I do it, and importantly, what should I be looking for the establish if a round is too long?

Thanks,

-- L.

 

[Viper26]

What pistol, caliber and bullet?

 

[sigtactical]

is it what's called '''land to land measurement'''' intended to get the perfect COAL for any pistol ???

 

[Lojak]

Tanfoglio Match, 9mm. Various factory and commercial reloads, weighted from 115, 124 to 147. Right now I have a bunch of 124 commercial reloads at 1.115, but very susceptible to FTF's. It is definitely a tight chamber issue, but given the pistol is a "match" pistol, I'm very hesitant to have a gunsmith open it up further.

-- L.

 

[Viper26]

Tanfoglio Match, 9mm. Various factory and commercial reloads, weighted from 115, 124 to 147. Right now I have a bunch of 124 commercial reloads at 1.115, but very susceptible to FTF's. It is definitely a tight chamber issue, but given the pistol is a "match" pistol, I'm very hesitant to have a gunsmith open it up further.

-- L.

1.095 to 1.100 (depending on the bullet ogive) is probably more appropriate for your Tanfoglio.

 

[CeeZer]

Try polishing feedramp and chamber first, since it's FTFs.

 

[Viper26]

Are we talking about nosedives on the ramp, or the round not chambering all the way?

 

[Ganderite]

Are you seeing scuff marks all the way around the bullet, at the case mouth? That would suggest bullet must be seated deeper.

 

[G37]

Magazines are often the limiting factor for too much OAL.

One trick you can try, use a candle and burn the seated bullet (get it covered in soot) then drop the cartridge into the chamber and pull it out. You can easily see if it is making contact and where.

 

[bear.23]

Commercial reloads are your problem.. I have a 5906 with a match chamber.. reloads won't chamber unless I resize them first... I have a lee factory size die and even with that there is a chance they won't... I have a roll sizer just waiting to get 9mm dies

 

[Lojak]

It is difficult to determine what is exactly happening with the FTF's. The slide closes most of the way, except a final 2-3mm. Racking the slide back to eject is extremely difficult, but if the slide is push forward with some force, the round will load. Is it getting hung up on the feed ramp? I don't think so, as I cannot see into the chamber at all.

I had purchased one thousand rounds of reloaded commercial from Wentworth in Hamilton, and it is made by Frank in Kitchener I believe. The OAL of those rounds is 1.115 typically. I've used my single stage press with Lee dies to reduce the OAL to 1.100, with no pressure signs on the spent case or primer. Going lower with those rounds will see some pressure signs on the primer. With an OAL of 1.100, I usually have no problems. Anything higher than 1.102 and FTF's will occur.

Now for the fun part.. the Ogive and/or bullet shape really does play a factor. I had picked up a few hundred Winchester 147gr "Lawmen" rounds, with a flat nose, which measure 1.115 +- 0.003, and find about 1 in 10 FTF. Conversely, a box of Wolf reloads at 1.115 +- 0.003 almost always fail.

I like the idea of marking the bullet to see if it hits the lands, though I think I'll use a marker if testing loaded rounds

Is there a way to feel if a bullet has it the lands? I don't think so, as I don't really feel a difference between any of the rounds I've listed when those are dropped into a barrel. But its worth asking, maybe I'm missing something.

Thanks,

-- L.

PS- I'm not going to polish the feed ramp or chamber yet, but that's something to consider. I have run a cotton q-tip across looking for burrs, and did not find any.

 

[Lojak]

Well, maybe I'm just an idiot..

CeeZer's suggestion to have the feed ramp polished prompted me to look at it again carefully. This is what I found on the right side, upper portion of the feedramp:

It appears to be worse than a burr, almost like a cut edge. That may very well be playing a part in this whole affair. I'll be taking it to a 'smith asap.

Thanks,

-- L.