If one were to build a bulletproof AR 15 bolt, meaning no cracking of
lug shearing with automatic use and slow wear , what material would
you make it out of? What treatment processes would you do attain this
strength?

trg-s338

trg-s338 wrote:

If one were to build a bulletproof AR 15 bolt, meaning no cracking of
lug shearing with automatic use and slow wear , what material would
you make it out of? What treatment processes would you do attain this
strength?

trg-s338

K*********ium
Heat treat by *************** *** ********** ***** ** ************ ***
****** finally ******** ** ************* *************** **.

I***

* Censored by FSB

"trg-s338" wrote in message
oups.com...
If one were to build a bulletproof AR 15 bolt, meaning no cracking of
lug shearing with automatic use and slow wear , what material would
you make it out of? What treatment processes would you do attain this
strength?

trg-s338

obviously unobtanium is the correct material

On Tue, 02 Oct 2007 01:04:38 -0000, trg-s338
wrote:

If one were to build a bulletproof AR 15 bolt, meaning no cracking of
lug shearing with automatic use and slow wear , what material would
you make it out of? What treatment processes would you do attain this
strength?

trg-s338


Personally..Id buy one. They are cheap, and properly head treated and
made of the proper materials.

Im considering building a California AR, but will be using a
commercial bolt.

Gunner

On Oct 2, 8:52 am, Gunner Asch wrote:
On Tue, 02 Oct 2007 01:04:38 -0000, trg-s338
wrote:

If one were to build a bulletproof AR 15 bolt, meaning no cracking of
lug shearing with automatic use and slow wear , what material would
you make it out of? What treatment processes would you do attain this
strength?

trg-s338

Personally..Id buy one. They are cheap, and properly head treated and
made of the proper materials.

Im considering building a California AR, but will be using a
commercial bolt.

Gunner

I apologise for failing to be more specific in the application. No
need for better than what's available for the 223 but
I've been considering a California AR15 in the 6.5mm Grendel. This
round exerting higher preasure on the bolt has been reported to crack
bolts of commercial origin or shear lugs. Even the developers of this
round have had occassional failure in their bolts. The commercial
rounds are downloaded to limit preasure development because of this
weak link in the system. Just wondering if one could be built without
the business considerations commercial manufacturers are subject to or
limited by. Materials like any of the various tool steels or exotic
metals like Inconel or other such materials able to handle the
stresses of an AR bolt in this application, are any of these
appropriate?

trg-s338

"trg-s338" wrote in message
s.com...
On Oct 2, 8:52 am, Gunner Asch wrote:
On Tue, 02 Oct 2007 01:04:38 -0000, trg-s338
wrote:

If one were to build a bulletproof AR 15 bolt, meaning no cracking of
lug shearing with automatic use and slow wear , what material would
you make it out of? What treatment processes would you do attain this
strength?

trg-s338

Personally..Id buy one. They are cheap, and properly head treated and
made of the proper materials.

Im considering building a California AR, but will be using a
commercial bolt.

Gunner

I apologise for failing to be more specific in the application. No
need for better than what's available for the 223 but
I've been considering a California AR15 in the 6.5mm Grendel. This
round exerting higher preasure on the bolt has been reported to crack
bolts of commercial origin or shear lugs. Even the developers of this
round have had occassional failure in their bolts. The commercial
rounds are downloaded to limit preasure development because of this
weak link in the system. Just wondering if one could be built without
the business considerations commercial manufacturers are subject to or
limited by. Materials like any of the various tool steels or exotic
metals like Inconel or other such materials able to handle the
stresses of an AR bolt in this application, are any of these
appropriate?

Do you know the material and heat treatment of the original? If you want
something better, you have to know what you're starting with.

(When I was at Wasino we were facing those bolts in a trial run for Colt,
but I don't remember the material. Sorry.)

--
Ed Huntress

On Oct 2, 1:26 pm, "Ed Huntress" wrote:

Do you know the material and heat treatment of the original? If you want
something better, you have to know what you're starting with.

(When I was at Wasino we were facing those bolts in a trial run for Colt,
but I don't remember the material. Sorry.)


Ed is certainly right. You could waste a lot of time and money by
trying to reinvent the wheel.

Off the cuff response: S-class tool steels are make for severe shock
environments Things like blanking and cold-heading, where less rugged
tool steels will shatter.

You can also investigate powered-metallurgy tool steels. Bloody tough
to machine (not for amateurs) and very expensive, but if you're able
to build your part, it will likely be about as strong as can be made.

You should discuss the application with a tool steel apps engineer.
You'll also get information on proper heat-treat (likely impossible at
home - will need to be farmed out).

(this advise is worth exactly what you paid for it)

Regards,

Robin

On Oct 2, 5:12 pm, "Robin S." wrote:
On Oct 2, 1:26 pm, "Ed Huntress" wrote:



Do you know the material and heat treatment of the original? If you want
something better, you have to know what you're starting with.

(When I was at Wasino we were facing those bolts in a trial run for Colt,
but I don't remember the material. Sorry.)

Ed is certainly right. You could waste a lot of time and money by
trying to reinvent the wheel.

Off the cuff response: S-class tool steels are make for severe shock
environments Things like blanking and cold-heading, where less rugged
tool steels will shatter.

You can also investigate powered-metallurgy tool steels. Bloody tough
to machine (not for amateurs) and very expensive, but if you're able
to build your part, it will likely be about as strong as can be made.

You should discuss the application with a tool steel apps engineer.
You'll also get information on proper heat-treat (likely impossible at
home - will need to be farmed out).

(this advise is worth exactly what you paid for it)

Regards,

Robin


Thanks for at least attempting to answer my post. For my personal
edification and learning, I will look up the materials
you mentioned. Yes most heat treat processes are beyond my realm.

On Tue, 02 Oct 2007 10:08:03 -0700, trg-s338
wrote:

On Oct 2, 8:52 am, Gunner Asch wrote:
On Tue, 02 Oct 2007 01:04:38 -0000, trg-s338
wrote:

If one were to build a bulletproof AR 15 bolt, meaning no cracking of
lug shearing with automatic use and slow wear , what material would
you make it out of? What treatment processes would you do attain this
strength?

trg-s338

Personally..Id buy one. They are cheap, and properly head treated and
made of the proper materials.

Im considering building a California AR, but will be using a
commercial bolt.

Gunner

I apologise for failing to be more specific in the application. No
need for better than what's available for the 223 but
I've been considering a California AR15 in the 6.5mm Grendel. This
round exerting higher preasure on the bolt has been reported to crack
bolts of commercial origin or shear lugs. Even the developers of this
round have had occassional failure in their bolts. The commercial
rounds are downloaded to limit preasure development because of this
weak link in the system. Just wondering if one could be built without
the business considerations commercial manufacturers are subject to or
limited by. Materials like any of the various tool steels or exotic
metals like Inconel or other such materials able to handle the
stresses of an AR bolt in this application, are any of these
appropriate?

trg-s338

If you want to re-design the bolt of an AR15 then the first step is to
determine what material and tensile strength, i.e., heat treatment,
was used for the original bolt. As I believe the original bolt was
chrome plated you will need to advise the testing lab of this fact. In
addition chrome plating is known to be a source of hydrogen
enbrittlement so the lab should also test for that.

Once you have a lab report as to material and strength in hand you
need to consult a competent engineer with experience in designing high
strength steel components who can advise you of the feasibility of
re-manufacturing the bolt. It may even be that given the pressures
developed by the new cartridge that the present bolt design cannot be
made to successfully withstand the pressures in which case you will
need to redesign the locking system for these higher forces.

This is probably not what you want to hear but the empirical method of
"suck it and see" is going to bust a lot of receivers before you get
it right.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

wrote in message
...

snip


If you want to re-design the bolt of an AR15 then the first step is to
determine what material and tensile strength, i.e., heat treatment,
was used for the original bolt. As I believe the original bolt was
chrome plated you will need to advise the testing lab of this fact. In
addition chrome plating is known to be a source of hydrogen
enbrittlement so the lab should also test for that.

Once you have a lab report as to material and strength in hand you
need to consult a competent engineer with experience in designing high
strength steel components who can advise you of the feasibility of
re-manufacturing the bolt. It may even be that given the pressures
developed by the new cartridge that the present bolt design cannot be
made to successfully withstand the pressures in which case you will
need to redesign the locking system for these higher forces.

This is probably not what you want to hear but the empirical method of
"suck it and see" is going to bust a lot of receivers before you get
it right.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

If you call Colt and persist, they'll probably tell you what it's made of.
Just don't tell them you want to improve it. g

--
Ed Huntress

On Oct 2, 6:41 pm, wrote:
On Tue, 02 Oct 2007 10:08:03 -0700, trg-s338
wrote:



On Oct 2, 8:52 am, Gunner Asch wrote:
On Tue, 02 Oct 2007 01:04:38 -0000, trg-s338
wrote:

If one were to build a bulletproof AR 15 bolt, meaning no cracking of
lug shearing with automatic use and slow wear , what material would
you make it out of? What treatment processes would you do attain this
strength?

trg-s338

Personally..Id buy one. They are cheap, and properly head treated and
made of the proper materials.

Im considering building a California AR, but will be using a
commercial bolt.

Gunner

I apologise for failing to be more specific in the application. No
need for better than what's available for the 223 but
I've been considering a California AR15 in the 6.5mm Grendel. This
round exerting higher preasure on the bolt has been reported to crack
bolts of commercial origin or shear lugs. Even the developers of this
round have had occassional failure in their bolts. The commercial
rounds are downloaded to limit preasure development because of this
weak link in the system. Just wondering if one could be built without
the business considerations commercial manufacturers are subject to or
limited by. Materials like any of the various tool steels or exotic
metals like Inconel or other such materials able to handle the
stresses of an AR bolt in this application, are any of these
appropriate?

trg-s338

If you want to re-design the bolt of an AR15 then the first step is to
determine what material and tensile strength, i.e., heat treatment,
was used for the original bolt. As I believe the original bolt was
chrome plated you will need to advise the testing lab of this fact. In
addition chrome plating is known to be a source of hydrogen
enbrittlement so the lab should also test for that.

Once you have a lab report as to material and strength in hand you
need to consult a competent engineer with experience in designing high
strength steel components who can advise you of the feasibility of
re-manufacturing the bolt. It may even be that given the pressures
developed by the new cartridge that the present bolt design cannot be
made to successfully withstand the pressures in which case you will
need to redesign the locking system for these higher forces.

This is probably not what you want to hear but the empirical method of
"suck it and see" is going to bust a lot of receivers before you get
it right.

Bruce in Bangkok
(brucepaigeATgmailDOTcom)


You are probably correct in that the bolt as designed was not meant
to handle the increased preasure of a bigger cartridge, and that to
successfully get the bolt reliable, a major redesign of the lockup
system needs to be addressed. All that is of course beyond the
tinkering/hobby realm of mine. Busting a lot of receivers through
bolt lug shearing, lockup failure and the resultant explosion is not
my cup of tea either. Thanks for the response.

PS--

On Thu, 04 Oct 2007 04:46:29 -0000, trg-s338
wrote:

On Oct 2, 6:41 pm, wrote:
On Tue, 02 Oct 2007 10:08:03 -0700, trg-s338
wrote:



On Oct 2, 8:52 am, Gunner Asch wrote:
On Tue, 02 Oct 2007 01:04:38 -0000, trg-s338
wrote:

If one were to build a bulletproof AR 15 bolt, meaning no cracking of
lug shearing with automatic use and slow wear , what material would
you make it out of? What treatment processes would you do attain this
strength?

trg-s338

Personally..Id buy one. They are cheap, and properly head treated and
made of the proper materials.

Im considering building a California AR, but will be using a
commercial bolt.

Gunner

I apologise for failing to be more specific in the application. No
need for better than what's available for the 223 but
I've been considering a California AR15 in the 6.5mm Grendel. This
round exerting higher preasure on the bolt has been reported to crack
bolts of commercial origin or shear lugs. Even the developers of this
round have had occassional failure in their bolts. The commercial
rounds are downloaded to limit preasure development because of this
weak link in the system. Just wondering if one could be built without
the business considerations commercial manufacturers are subject to or
limited by. Materials like any of the various tool steels or exotic
metals like Inconel or other such materials able to handle the
stresses of an AR bolt in this application, are any of these
appropriate?

trg-s338

If you want to re-design the bolt of an AR15 then the first step is to
determine what material and tensile strength, i.e., heat treatment,
was used for the original bolt. As I believe the original bolt was
chrome plated you will need to advise the testing lab of this fact. In
addition chrome plating is known to be a source of hydrogen
enbrittlement so the lab should also test for that.

Once you have a lab report as to material and strength in hand you
need to consult a competent engineer with experience in designing high
strength steel components who can advise you of the feasibility of
re-manufacturing the bolt. It may even be that given the pressures
developed by the new cartridge that the present bolt design cannot be
made to successfully withstand the pressures in which case you will
need to redesign the locking system for these higher forces.

This is probably not what you want to hear but the empirical method of
"suck it and see" is going to bust a lot of receivers before you get
it right.

Bruce in Bangkok
(brucepaigeATgmailDOTcom)


You are probably correct in that the bolt as designed was not meant
to handle the increased preasure of a bigger cartridge, and that to
successfully get the bolt reliable, a major redesign of the lockup
system needs to be addressed. All that is of course beyond the
tinkering/hobby realm of mine. Busting a lot of receivers through
bolt lug shearing, lockup failure and the resultant explosion is not
my cup of tea either. Thanks for the response.

PS--


You know, I've been thinking about your problem and it seems funny to
me that bolt lugs are cracking. Years ago P.O. Ackley did some tests
on the actual thrust exerted on the bolt when the gun is fired and if
I remember correctly because of the cartridge expanding as the powder
burns it grips the sides of the chamber and actual thrust forces,
against the bolt were far lower then chamber pressure would have one
believe.

Another point, many bolt guns are converted to higher power cartridges
then originally intended, witness some of the chamberings for the poor
old '98 Mauser, military, that has a relatively weak (compared to
modern actions) bolt and receiver.

How much higher chamber pressure is this new round developing and what
is the cartridge head size compared to the normal AR-15?

Another point, if you are firing a higher powered cartridge then
unless you either limit the amount of gas vented to the action,
increase the weight of the bolt and carrier or increase the strength
of the recoil spring the bolt is going to slam back against the stops
with considerable more force then normal. Might this have any effect
on bolt cracking?

If chamber pressure is higher then gas pressure is higher - is the
bolt starting to unlock earlier in the cycle so that higher pressure
is exerted against a partially opened lock?

These are just random thoughts but it might be interesting to see what
happens if, say a gas port is plugged or a very heavy recoil spring
fitted.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

According to Gunner Asch :

[ ... ]

Personally..Id buy one. They are cheap, and properly head treated and
made of the proper materials.

Well ... this is about as far back in the thread as I can go at
the moment to post this.

Mostly -- every time I see the subject line above, I keep
thinking "But shouldn't the bullet be going the other direction -- away
from the bolt?" :-)

Enjoy,
DoN.

--
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