Overgassing in hot weather temperatures?

[Spooky1]

I prefer to recommend Colt extractor springs because I have first hand experience with them.

I have very little hands on experience with the Sprinco spring. However, I did have a discussion on the subject with Will Larson who had extensive experience working on ARs (along with other families of weapons) in a combat zone as well as here in the US. He thought enough of the Sprinco spring that he recommended Sionics and SOLGW use them in their ARs. Will's bona fides were good enough that I recommend the Sprinco springs based on his say so. I haven't heard any complaints from anyone using the Sprinco spring.

I see no reason to replace a Sprinco spring with a Colt spring or vice versa.

Will passed away not long after I took his armorer's course. He is missed.

Thank you. I wish I had joined instead of just nosed about while Mr Will was still with us.

[Spooky1]

We were likely in the same class. Anyhow straight from the M4C archives 2019 by Will himself

[The Colt copper washed extractor spring is a good option, as is the Sprinco enhanced spring. I have also used (and still have) BCM enhanced springs as well. Any of them will work.]

Nuff said?

Thank you also, haven't figured out how to quote two different people in the same post or I would have thanked you and MistWolf at the same time.

[lysander]

How much does the bolt speed change with a dramatic amount of erosion?

It not really that simple. Here is a test where the cyclic rate was recorded over an endurance test of 6,000 rounds:

(click to enlarge)
Attachment 66200

As you can see, there is a lot of variation.

[lysander]

In graphic form:
Attachment 66201

[T2C]

It not really that simple. Here is a test where the cyclic rate was recorded over an endurance test of 6,000 rounds:

(click to enlarge)
Attachment 66200

As you can see, there is a lot of variation.

I did not know if bolt speed would change the accuracy of a match rifle. I changed barrels when accuracy was over .75 MOA when I competed.

I change barrels on carbines when accuracy is over 2.5 MOA at 300 yards with M193.

[opngrnd]

I did not know if bolt speed would change the accuracy of a match rifle. I changed barrels when accuracy was over .75 MOA when I competed.

I change barrels on carbines when accuracy is over 2.5 MOA at 300 yards with M193.

How many rounds did the barrels tend to last before being changed?

[lysander]

I did not know if bolt speed would change the accuracy of a match rifle. I changed barrels when accuracy was over .75 MOA when I competed.

I change barrels on carbines when accuracy is over 2.5 MOA at 300 yards with M193.

Throat and/or muzzle wear will degrade accuracy long before problems due to gas port erosion start to manifest themselves . . . .

[T2C]

How many rounds did the barrels tend to last before being changed?

I changed stainless match barrels between 3000 and 4000 rounds. The barrels were still serviceable and I sold them to people who shot at distances of 300 yards and closer and could not tell the difference between one of my used barrels and a new barrel. I sold the bolt that was used with the barrel.

I change carbine barrels between 8,000 and 10,000 rounds to maintain sub 2-1/2 MOA accuracy at 300 yards with 55g FMJ. A stripped bolt will not close on a field gauge when I scrap them. If I push a barrel until a stripped bolt will close on a Field gauge, I usually see 12,000 rounds of service life.

An interesting thing about the AR-15 platform is that I did not notice a marked difference in accuracy between serviceable magazines like I did with the M1A.

[Spooky1]

I changed stainless match barrels between 3000 and 4000 rounds. The barrels were still serviceable and I sold them to people who shot at distances of 300 yards and closer and could not tell the difference between one of my used barrels and a new barrel. I sold the bolt that was used with the barrel.

I change carbine barrels between 8,000 and 10,000 rounds to maintain sub 2-1/2 MOA accuracy at 300 yards with 55g FMJ. A stripped bolt will not close on a field gauge when I scrap them. If I push a barrel until a stripped bolt will close on a Field gauge, I usually see 12,000 rounds of service life.

An interesting thing about the AR-15 platform is that I did not notice a marked difference in accuracy between serviceable magazines like I did with the M1A.

Were your Carbine Barrels Stainless Steel also?

[bulletproofwelding_1]

Why worry about it do you think are boys over in the sand box care were they brass hits.