AMT Guns forum

Forum Home Forum Home > Auto Mag Pistol > Message Board
  New Posts New Posts RSS Feed - Fast Powders and AutoMags
  FAQ FAQ  Forum Search   Register Register  Login Login

Fast Powders and AutoMags

 Post Reply Post Reply Page  <1 345
Author
Message
Bellarmament View Drop Down
International Auto Mag
International Auto Mag


Joined: 17 May 2016
Status: Offline
Points: 52
Post Options Post Options   Thanks (0) Thanks(0)   Quote Bellarmament Quote  Post ReplyReply Direct Link To This Post Posted: 31 Jan 2018 at 5:40pm
Hopefully those interested have had time to read the excellent article written by Allan Jones for shooting times. Link below:

http://www.shootingtimes.com/ammo/ammunition_st_cuppsireloaddata_200905/

I only want to add a couple of comments. Most gunsmiths or design engineers are not ballisticians and most ballisticians are not gunsmiths or design engineers and most gunsmiths are not design engineers or ballisticians. In my opinion the word Gunsmith is used way too loosely these days.

I agree that the over pressure results obtained during his testing (like with the 10mm) will not harm the stout pressure gun or pressure barrel they use in peak pressure and pressure curve determination. Most of the pressure guns used now have a 15 inch length barrel (SAAMI Standard) with one inch diameter (unless a larger bore diameter dictates otherwise). Alan may have used shorter barrels for handgun caliber testing and I have not purchased a new Sierra manual to see if barrel length is listed as a determiner for data. Depending on the length of the barrel peak pressure and adequate pressure curve to the drop off can be measured in shorter barrels dependent on the burn rate of the powder.

My point is the pressure gun being used is simply a strong stout test fixture and bears no semblance to the Auto Mag or any other type semi auto pistol. To make a comment that brief over pressure is happening so fast that no harm is done is debatable and questionable in my opinion. Almost like saying if I kick you in the balls fast enough you will not feel it or suffer any ill effects. Metal compression (cold forging) and metal fatigue are real issues that cannot be accessed in a particular firearm without testing and analyzing in a particular firearm (service life up to and including destructive testing).

I have several friends who have had case blowouts in Delta Elite Colt pistols in 10mm and many instances of this type happening in different firearms can be researched on the internet ( many caused by inadequately supported cartridge casing at the ramp cut in the barrel). Over pressure may not harm one type design firearm but may have undesired consequences in a different design firearm. Do a search for 10mm kaboom on your computer if interested.

I personally stay away from fast burning powders unless used for light to moderate target loads. I am not a ballistician but personally know several retired Lake City Arsenal and private sector ballisticians that I ping for knowledge and opinions when I am lacking. In some recoil operated pistols the amount of fast burning powder needed produce the recoil energy to operate the pistol reliably may possibly cause early peak over pressure that could cause damage in some pistols. Unfortunately Auto Mag pistols are expensive to do destructive testing evaluations so I prefer to stay on the safe side with slower burn rate powders.

Time for my quick can of Ravioli. LOL

Tim
Back to Top
Bellarmament View Drop Down
International Auto Mag
International Auto Mag


Joined: 17 May 2016
Status: Offline
Points: 52
Post Options Post Options   Thanks (0) Thanks(0)   Quote Bellarmament Quote  Post ReplyReply Direct Link To This Post Posted: 01 Feb 2018 at 2:44am
I have had several PM's regarding free space, lug space and head space. I will make an attempt to explain this better.

If your pistol unloaded with the bolt in battery has a distance between the face of the barrel extension lugs and rear of the bolt lugs of .004 then your free space is .004.

If the same unloaded pistol with the bolt in battery has a distance from the bolt face to the case mouth stop in the chamber a distance of 1.296 and you trim your casing to 1.292 you have .004 head space and still have the .004 lug space.

Add the two together and you have .008 of total tolerance that will be violently taken up in a micro second when the cartridge is ignited when the trim length is 1.292.

In the same pistol if the casing was trimmed at 1.298 you would only have .002 tolerance to take up or basically your head space would be fine but you would still have .002 lug space which is easier on the pistol and since .001 to .002 in my opinion is necessary for a smooth and reliable functioning pistol this will be about the best you can do due to the design of the firearm.

The goal is to trim the cartridge case to a sufficient length to only allow a minimum of functional lug space.

Hope this clears up any confusion and if not just drop me a line.

Thanks
Tim

Back to Top
Bellarmament View Drop Down
International Auto Mag
International Auto Mag


Joined: 17 May 2016
Status: Offline
Points: 52
Post Options Post Options   Thanks (0) Thanks(0)   Quote Bellarmament Quote  Post ReplyReply Direct Link To This Post Posted: 02 Feb 2018 at 2:33am
Originally posted by Olestick Olestick wrote:

Im having no luck  with the 357 BBL on my amp I use 158 gr jhp 21.5 gr 296 cci mag primers  in Starline
brass  I also tried H-110 in diffront weights from the book
I bought the gun used at gun broker with the 357 and 44 mag bbl the 44 works most time
 I know these guns are finnacky but I haven't got the 357 bbl to cycle even once.
I read u r article and I have no reformed brass from 308 . I do have 44 mag brass formed from 308 cases
maybe  I can make some from them.
  I appreciate any  help  
  Jer Ouch


A firearm not cycling is a broad statement. It is difficult to diagnose a problem without more info.
The quickest way to attempt a diagnosis is to video the pistol while being fired hopefully in slow motion mode on a I Phone or similar device. We need to see where the pistol is failing. In what area is it failing? The video will tell me if you are limp wristing the pistol and I will also be able to tell if your upper is moving rearward properly and if the bolt is being launched to the rearward limit necessary for function.

1. Is the pistol mechanically able to perform ( broken, damaged parts, weak springs etc)
2. Is it failing to load?
3. Is it failing to fire the cartridge?
4. Is it failing to extract?
5. Is it failing to eject?
6. Is it failing to load the next round?
7. Are there any signs from reading the fired brass that would indicate a problem.
8. Is the ammunition adequate to function the pistol

First off lets check the mechanics of the upper. Be observant and be cautious as these firearms can bite and scratch!! Like Chevy Chase in Caddy Shack said of the golf balls the same can be applied to analyzing a firearm problem. See the gun, be the gun. Concentrate! Remove any live ammunition from your work area and make sure the pistol is not loaded.

Here we go.  Insert an empty magazine, retract the bolt  the hold open should engage and hold the bolt to the rear. Now remove the .357amp upper and make sure no one has removed the accelerator. If the accelerator is there look for any damage or binding. The accelerator should be able to rock fore and aft with finger pressure freely with no binding against the accelerator block.

Now lets check accelerator timing. Put the .357amp upper back onto the pistol and lower the bolt gently to see if there is any resisting or binding when lowering the bolt. Make sure the bolt moves freely forward and cams over the roughly 22 degrees to full lock into battery. Never ever drop the bolt with the safety lever without a cartridge in an inserted magazine ready to be loaded!

Get a towel and put it on a solid surface. Put an empty magazine into the pistol and place the muzzle down on the towel and press down. You will see the hammer move back and the upper move rearward. Push until the upper stops moving rearward and hold in place. Wnen pushing the upper downward the bolt due to interaction with the rotation pin will turn the bolt to unlock. Was it a smooth transition or rough and grinding?  With your free hand pull the cocking piece slowly to the rear and retract the bolt until the hold open catches the bolt and holds it rearward. If when you initially began pulling the bolt to the rear you met with resistance that took a snatch to overcome then you may have an accelerator fitment problem. Early or late accelerator engagment with the bolt can cause problems. With the muzzle pressed firmly down your accelerator should have started the bolt rearward at the proper rotational attitude and linear distance to not grab or grind on your barrel extension lugs. If you felt a grab or grind remove the upper and take a flash light and look into the bottom of the barrel extension. You will be able to see the condition of the uppermost locking lugs. Look to see if there is any peening or deformation of the lugs you are able to see. The lower lugs can only be checked adequately with a good bore scope. You can buy a bore scope for your I phone or Android off ebay that works well enough to view and snap a picture of the face of the lugs. If either of the aforementioned is the problem then stop and have the pistol repaired by a competent Auto Mag gunsmith.

While you are at it pick up the frame and examine the bolt locking lugs carefully with a good magnifying glass and look for cracks, chips or deformation then check the function of the ejector and extractor. The ejector should allow itself to be pressed slightly below the bolt face and should have good return spring pressure (quick and snappy). Check the extractor with a small brass punch. The extractor should move with spring resistance outward enough to accept a cartridge rim so the extractor rim catch area should be able to move slightly past the interior on the ring of metal around the bolt face that surrounds a cartridge and then snap briskly back into place when released. If these two bolt issues are fine then take an  empty cartridge case and press the case head into the bolt face and make sure there is no entry binding or catching on the face of the extractor it there is take a round fine honing stone and chamfer for smooth entry. Check the firing pin by taking the tip of an ink pen and push forward on the rear of the firing pin and hold and inspect the protruding tip of the firing pin. It should have a rounded tip free of damage. Make sure the firing pin spring quickly and freely returns the firing pin when you pull the ink pin away from the rear of the firing pin. The reason an ink pen is good to use is it pushes the firing pin far enough through the bolt face to get a good look at the firing pin tip. A weak firing pin spring can cause light primer strikes. Check your fired brass to insure you have adequate indentation.

Naturally if you have a damaged bolt do not fire the pistol and have it repaired by a competent Auto Mag gunsmith.

I like to remove the bolt and examine the bolt frame ring for cracks and elongation at the rotation pin hole in the bolt ring. The bolt frame ring should stand perpendicular to the top shelf of the frame. If the bolt ring on the frame is leaning rearward or has an elongated rotation pin hole then my advice is to not fire the pistol and have it repaired by a competent Auto Mag gunsmith.

Guess we need to stop here. Not knowing what tools you have or how much Auto Mag experience you have I do not want to overload you or exceed your limitations.

Unfortunately if you have bolt damage you likely have barrel extension lug damage also but can have extension lug damage without any visible bolt damage. If this is the case it would be best to just purchase a new Classic upper as it comes with a new bolt. I feel the new uppers should be fitted to your frame by a factory gunsmith as the bolt safety tappet needs to be checked for proper function with the new bolt.
 

If everything is OK then clean the pistol, lubricate and reassemble and when at the range take a video ( close but safe distance when video is taken) and post it or at the very least tell at what point a failure to cycle is occurring. Make sure those recoil rods are tight!

If I missed anything guy's please chime in.

I would like to thank Ian for the use of his website to juggle info.

I am no longer with Auto Mag and changes could have been made to the new design I may not be aware of. Even though most of the info applies also to the new design pistols I mainly post regarding the old original pistols.

Hope this helps
Tim



Back to Top
Olestick View Drop Down
Baby Auto Mag
Baby Auto Mag
Avatar

Joined: 11 Feb 2016
Location: New york
Status: Offline
Points: 14
Post Options Post Options   Thanks (0) Thanks(0)   Quote Olestick Quote  Post ReplyReply Direct Link To This Post Posted: 04 Feb 2018 at 4:16pm
Thanks for the info it was very useful
 I uped my 296 load from 22 gr.  to 23 gr  i tried both .357 starline and made some .357 from win 308  brass the gun function was improved  by far , neither  brass loaded  same components  made any difference that I could tell .. i think i will try  23.2 grains  of 295Smile
at this time my AMT will fire 3 rounds of .357 no problem 
thanks 
Olestick

Back to Top
Olestick View Drop Down
Baby Auto Mag
Baby Auto Mag
Avatar

Joined: 11 Feb 2016
Location: New york
Status: Offline
Points: 14
Post Options Post Options   Thanks (0) Thanks(0)   Quote Olestick Quote  Post ReplyReply Direct Link To This Post Posted: 04 Feb 2018 at 4:25pm
Ok 
 does anyone have the contact info of a good AMT Automag gunsmith  that would be nice if i needed parts or service
Thanks Olestick
Back to Top
Gerry View Drop Down
Callahan's Auto Mag
Callahan's Auto Mag


Joined: 08 Mar 2008
Location: MI
Status: Offline
Points: 1072
Post Options Post Options   Thanks (0) Thanks(0)   Quote Gerry Quote  Post ReplyReply Direct Link To This Post Posted: 13 Apr 2018 at 12:46am
Originally posted by Bellarmament Bellarmament wrote:

While we are on the topic of hand loading I feel this is important.

Your case length is critical to a long service life!!

Go and no go gauges are of limited use with the Auto Mag pistol. Here is a photo of the lug space / head space gauge I made for the .44 amp Auto Mag pistols. It operates similar to a pull through reamer.



Many of you after gauging would find you are trimming your casings way short! This causes excessive lug battering and lug compression and increases the lug battering as a vicious cycle as lug space worsens.

To use the gauge you first remove the upper then remove the extractor and ejector (this can be done without removing the bolt). Then retract the bolt and engage the hold open. Then remove the handle from the gauge (set gauge with a caliper to 1.350) and insert from the rear and re-install the upper and gently lower the bolt. The bolt will not cam over to lock because the gauge is set long. Install the handle on the gauge rod that is extended out of the muzzle and turn the handle ANTI clockwise until the bolt cams over to full lock into battery.

Then retract the bolt and engage the hold open to hold the bolt to the rear and remove the upper. Then remove the handle from the gauge rod and remove the gauge and take the caliper and measure length.This measurement will give you the minimum in lug space and indicate the trimmed case length and thereby increase the service life of the pistol if casings are trimmed accordingly. Some of the time you will need to trim cases .001 to .002 less than the gauge indicates to allow the bolt to be retracted easily and the pistol to function smoothly.

I have seen casings trimmed so short the lug space was maxed out and
the head space became an alarming issue to the point the extractor could not snap over the case rim and was pushed forward by the ejector.
Since the firing pin does not have a protrusion stop the firing pin could reach out and set off the cartridge. The case head will slam into the bolt face and slam the bolt lugs against the barrel extension lugs. Yes I know the upper will move rearward but the damage is still imparted. Much like holding your hand in the air and letting me hit it full swing with a baseball bat. Your hand will move when struck but it will still hurt and cause damage!

I personally blew up a .45 Winchester Magnum Auto Mag (Winchester factory loads) that was running .012 lug space to prove my point as someone " in the know" swore the Auto mag would shoot with .015 lug space. Not so as it immediately sheared the bolt lugs!

Photo below is one of the worst lug battering / lug setback cases on a Pasadena .44amp I have ever seen. .016 lug space with a 1.298 trimmed casing (gauged at 1.314).  Even if you could find a casing long enough to take up the lug space you would lose .016 off your dwell time to helix opening by moving the bolt that far rearward. Also there is lug chipping and the wear and impact damage is uneven. The bolt safety detent cut on the bolt of the old pistols (comma type and smiley type as they are referred to) would allow pistols to be in battery and able to fire when dangerous or damaging tolerances were occurring.  Not so with the new Auto Mag pistols with the redesigned bolt safety tappet (disconnector) detent along with a properly fitted bolt safety tappet.



You can also find your distance to helix opening with this gauge also. After the bolt cams into full battery just reverse and turn the gauge rod clockwise. You will see the upper begin to move rearward. Look at the bolt through the ejection port to detect the earliest rotational movement then stop turning the handle. Remove the gauge as explained earlier and measure with your caliper. Subtract your earlier case length measurement from the dwell to helix opening measurement and there you have your dwell distance. If I remember correctly a normal pistol should run around .100 to start of helix opening. This distance gives the bullet time to exit the barrel and pressure to subside before the bolt begins rotation to unlock.

I have also seen pistols where the barrel latch had metal removed from the face that contacts the run out slot in the extension lug to allow the upper to move forward to decrease lug space. In these cases the casing trim length would still need to be gauged as you have lengthened the distance from the bolt face to the end of the chamber.

I apologize for another long winded post.

Kind regards
Timothy Bell

PS: What determines the free lug space on your pistol (unloaded with bolt in battery)? On the old Auto Mag pistols it varied.
The forward cessation of bolt movement was ended either by the cocking piece against the frame end of the recoil tubes or the rotation pin at the rear of the slot in the bolt or the cocking piece bottoming out against the rear of the barrel extension.

What is optimal for your Auto Mag? The casing being trimmed to a sufficient length to only allow a minimum of functional lug space.

Here is an alternate method for finding trim length on your pistol. Although I do not use this method you can take a long sized casing and if the bolt will not cam over on said casing remove the casing and reduce length slightly and retry until the bolt cams over then measure the length. A brass case with thin walls does not make a good gauge in my opinion due to the case mouth not being substantial.

There is a good article by Shooting Times regarding fast powders and handgun cartridges. Though not specific to the Auto Mag I feel is a must read. Link below:

http://www.shootingtimes.com/ammo/ammunition_st_cuppsireloaddata_200905/

Any update on your tool?
Gerry
MI
Back to Top
 Post Reply Post Reply Page  <1 345
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.071 seconds.

 - amtguns.info All rights reserved