Some minor issues with a new gun

[peterk1234]

Well, my wife is a proud owner of a new STI Apeiro. We put a few hundred rounds through it and I had some interesting issues pop up. First, we went from a very light trigger pull when unloaded to one of about 50lbs with a mag in it. After some tinkering, I figured out it was the over travel screw on the trigger. Half a turn solved the problem. The mag must be pushing on something when inserted. All good.



Second issue was we had a number of times when the gun would not go completely into battery. The slide would stop with just an 1/8 of inch more to go. No amount of pushing was going help. So, today when we shot it, we immediately grabbed the bullet. I pulled the gun apart and did a plunk test. Bullet would not seat all the way into the chamber; it needed like a half a hair width more to go. This particular bullet was one of my reloads. I was not sure if it was a length issue or a crimp, so I needed to get back to the house with my reloading gear to figure it out. The weird thing is, I put the same bullet in the STI Marauder, and bang; no problem. Back at home I figured out it was length. I go for an OAL of 1.135 usually and I need to get down around 1.120 for it to plunk cleanly. So the base of my bullet must have been getting into the rifling is my guess. No biggie, problem solved. Anyone else ever have an issue with length like this? I am within spec at 1.135, so I guess I am surprised.



Last issue is feeding. It would happen with factory and reloads, although definitely more issues with my reloads. I use coated cone bullets. Now if I take one bullet in the mag and manually point the bullet up just a tiny bit before loading, it slides right into the chamber. Again, never an issue with the marauder. Is this just a tighter gun and I have to break it in for a while, or is this why people are purchasing the mag tuning kits?



Thank you



Pete

 

[CornCod]

Buy a couple of boxes of factory ammo to see if it is your handloading or the gun that is the problem.

 

[peterk1234]

I was having similar issues with factory ammo on the first day. We purchased a few more boxes yesterday, all different manufacturers, and it went into battery fine. The gun seems to be settling in a bit now that a few hundred rounds have been fired through it.

I need to do a bit more research regarding the feeding problem. It is not happening all the time, but I do want to completely eliminate it.

I am a bit stumped about the OAL problem. I will take a closer look tonight at my reloads to determine if I should play with the taper crimp a bit more. I feel that the barrel should not be that sensitive to length.

 

[edwardware]

I am a bit stumped about the OAL problem. . . I feel that the barrel should not be that sensitive to length.

Why wouldn't a match barrel be sensitive to COAL? Throating is generally one of the first dimensions to be reduced when creating a 'match' chamber.

Seat you bullets to plunk, and make sure your taper crimp is removing the mouth flare (and no more), and you'll be done. If you want to seat longer, you're going to need to ream the throat forward; I've done all my 1911s for exactly this reason.

 

[peterk1234]

Thanks edwardware, I appreciate the info. A barrel like this is a new world for me. So it is reasonable to assume then that match barrels will be sensitive to even the type of factory load is used. Time for me to do a bit of research on barrel throat length, me thinks. I am assuming the theory behind the shorter throat is that there is less movement possible for the bullet when it is seated in the chamber, therefore stabilizing the bullet quicker as it leaves the barrel. I have to admit, the gun is incredibly accurate; both my wife and I noticed that one immediately. It way better than we ever will be able to shoot it

 

[Cump]

I may have missed it in your post, but are you having the battery issues with factory ammo?

Do your bullets for the reloads have a wider ogive?

When I first reloaded HSM plated hp, I had battery issues, and I had to reseat with lighter charges and a oal shorter than spec. The bullets had a wider ogive that hit the rifling. But factory and other bullets chambered fine.

You may not need to ream the chambers, if so...

 

[peterk1234]

Cump,

I took some more measurements. My bullet diameters are .355 and the most recent box of factory ammo I purchased was .352 with an OAL 1.152. I think I understand what you are getting at. This is why my bullet length is more sensitive to OAL with my reloads; the max diameter of the bullet is getting into the rifling. One of the boxes of factory ammo also was using a larger diameter bullet than the most recent batch.

Fortunately, I am not even working near max charges with my powder, but I need to test to determine if there is any noticeable increase in power, now that I am seating a bit deeper.

 

[Cump]

When I seated deeper, I didn't need to reduce as much as I did, but in the end, I developed a very accurate load that functioned fine with a lighter recoil spring.

Half the fun of reloading is the problem solving.

 

[edwardware]

My bullet diameters are .355 and the most recent box of factory ammo I purchased was .352 with an OAL 1.152. I think I understand what you are getting at. This is why my bullet length is more sensitive to OAL with my reloads; the max diameter of the bullet is getting into the rifling.

Bingo, now you've got it. The throat on a 9mm SAAMI drawing is a 2° taper. A larger bullet will contact the throat further back.

My personal nemesis is 'match' chambered XDS9; I guess Springfield thought I was going to shoot Bullseye with a compact 9mm.

Just wait until you start casting! It is common to find that the bullet diameter that works well in a barrel requires very short COAL or reaming of the throat.