High mileage on a bolt?

[olp73]

Hi

I am building a new upper and have noticed that many barrel manufactures sell premium barrels with a bolt, as a kit. I understand that this is to make sure that it headspaces correctly and such, but is it wise to always change the bolt when swapping barrel? Or do you just measure the old one and go on shooting?

What do you consider high mileage on a bolt head.

[Dr Mitch]

The headspace is set when the barrel extension is put on the barrel.

I have never checked headspace, and have installed six barrels. I don't know anyone who checks headspace.

[jrswanson1]

Bolts are wear parts and need replacing. From a well respected armorer on Maryland Shooters:

As for a list, here are my generic maintenance schedule in regards to spare parts:

Every 7,500 Rounds it gets:
Colt Gold Extractor Spring (Other MFG's last 3-5K rounds so I dont use them)
Cam Pin
Gas Rings (NOT One Piece Rings)
Firing Pin Retainer (Not a Solid Retainer)
Action/Buffer Spring (Not needed if you use a Tubb Flat Wire Spring)

Every 15,000 Rounds it gets:
Stripped Bolt Head (check headspace with gauges)
3 Gas Rings (Not One Piece Rings)
Springco Ejector Spring
Ejector and NEW Roll Pin
Extractor
Colt Gold Spring
Chrome Firing Pin (Not Titanium, Melonite, or Unplated)
Firing Pin Retainer (Not a Solid Retainer)
Cam Pin (With a directional arrow scribed on the top)
Gas Tube and NEW Roll Pin
Action/Buffer Spring (Not needed if you use a Tubb Flat Wire Spring)
Hammer Spring (NOT Reduced Power)
Hammer & Trigger Pin (No Anti Rotational B.S.)

Rinse and repeat...

[MarkCO]

I check headspace. High mileage on a bolt kind of depends on the bolt... Not all are equal. I have no doubt a quality bolt can go 100k when used in a quality carrier.

I have 4 barrels, about 40k on my current match rifle with the same bolt.

[mikeyjones]

I check headspace. High mileage on a bolt kind of depends on the bolt... Not all are equal. I have no doubt a quality bolt can go 100k when used in a quality carrier.

I have 4 barrels, about 40k on my current match rifle with the same bolt.

What does the bolt face look like after 40k rounds?

Sent from my Z812 using Tapatalk

[MarkCO]

It is silver and very smooth.

[olp73]

Mine has 10K in a carbine gas system. Has a few dings on the luges.

[mpeltier]

I check headspace every build. Probably two dozen or so. Never found a combo out of spec. Using either new or re using a bolt. We have several hundred in use here at work with thousands of rounds on them (all Colts). I have yet to see a broken bolt or one wear to be out of spec as far as headspace is concerned. I personally believe its pretty rare to wear out a quality made bolt. (If properly cleaned and lubed)

[ziebart]

I have seen several broken bolts. Every one broke at the cam pin hole.

[MarkCO]

I have seen several broken bolts. Every one broke at the cam pin hole.

While that can be due to sloppiness of the carrier, it is rarely due to a bad bolt. Over Gassed (out of time) is a big part of bolts breaking at cam pin holes.

[ziebart]

Good to know.