Need buffer spring for .35 remington

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Schofield
Posts: 21
Joined: Mon Apr 13, 2020 12:16 pm

Need buffer spring for .35 remington

Post by Schofield »

I am in need of a buffer spring for my 1907 model 8 in .35 remington.

Fred
Posts: 133
Joined: Wed Feb 26, 2014 11:10 pm

Re: Need buffer spring for .35 remington

Post by Fred »

I want one too but since they're unavailable I've been thinking of trying to "make" one by modifying a stack of belleville washers...
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Phyrbird
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Re: Need buffer spring for .35 remington

Post by Phyrbird »

KISS -- Why not a round coil with near Identical specs? I'm interested...
Phyrbird
SOKY

Fred
Posts: 133
Joined: Wed Feb 26, 2014 11:10 pm

Re: Need buffer spring for .35 remington

Post by Fred »

Alright, the factory buffer spring's a stout little bugger being that it's a heavy square wire profile and only about 6 turns... It's hard to match that spring rate in a more conventional coil spring. If you assume it just has to be stiff enough to prevent the bolt/barrel assembly from crashing into the back of the receiver under recoil, then you can probably use one of these:

https://www.crower.com/valve-springs-si ... -vtec.html

.885" OD and .610" ID 2.310" free length.

~$7; shipping's probably extra.


Sure, It's a little long, but an angle grinder, a hand drill and 15 minutes will get you closer to the original 2.125" free length. But really, it only has to be long enough to allow the bolt/bolt carrier to unlock and extract the case.

Of course if the replacement spring is a lower spring-rate, which it probably is, then a full-pressure, heavy recoil load will compress the replacement spring more than a starting load. So IMO, testing should be done with the heaviest load you intend to run. If it works for the heavy load, then I'd check and see if it still works for lighter loads, if you intend to use any, and trim free-length as appropriate.

*edited since I made inaccurate assumptions in the mechanism's operation*
Last edited by Fred on Sat Jun 06, 2020 10:30 am, edited 1 time in total.

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Phyrbird
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Re: Need buffer spring for .35 remington

Post by Phyrbird »

Fred,
Thanks, we should follow up on an alternative like this. Might save a rifle or 2. Metal fatigue is going to get these springs one of these days.
Phyrbird
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Schofield
Posts: 21
Joined: Mon Apr 13, 2020 12:16 pm

Re: Need buffer spring for .35 remington

Post by Schofield »

sounds like it's worth testing. I am also looking into springs for dies used in stamping small metal parts. might take a little time but I will get back to you guys. how can I tell if the spring is over compressed when firing ?

Fred
Posts: 133
Joined: Wed Feb 26, 2014 11:10 pm

Re: Need buffer spring for .35 remington

Post by Fred »

Looking at the mechanism, I don't see much difference in function with a spring slightly longer or shorter than the factory piece. What is wrong with your short buffer spring that you are looking for a replacement? If your 1.970" length spring is being fussy, the first thing I'd do is to shim it to 2.125" and see what happens. The following is why I think that:

The barrel/bolt/bolt carrier assembly moves rearward with recoil energy. Three springs compress: the recoil spring, the action spring and eventually the buffer spring.

The buffer spring is the "rubber mallet" that unlocks the bolt from the barrel extension and the residual energy in the bolt/bolt carrier extracts the case and resets the hammer spring. In my M81, the bolt carrier will travel another ~5/8" after the barrel has reached the limit of travel.

That longer valve spring will start the unlocking/extraction operation slightly earlier in the cycle. I don't really see an issue with this going by the mechanism, assuming the bullet has left the barrel and the chamber pressure is relieved. Conversely, I also don't see any issue with a shorter spring either (which will delay the process), so long as there's room remaining for the bolt to unlock and extract the case after the barrel has reached the limit of travel.

It's possible that with a very short or soft buffer spring, the bolt carrier will impact the rear of the receiver before the barrel hits the limit of travel and could affect extraction. Is this what's happening to you?

With the factory buffer spring I very much doubt that the spring ever fully compresses, and I wouldn't worry about over compressing that Crower spring. It would take >200 lbs to reach coil bind.

Schofield
Posts: 21
Joined: Mon Apr 13, 2020 12:16 pm

Re: Need buffer spring for .35 remington

Post by Schofield »

Fred, thanks for the info. after looking into the rear of the receiver with a light I see no sign of the rear of it being hammered. no sign on the bolt either. so I decided to reassemble her and leave well enough alone. then upon tightening the barrel nut, it broke into three pieces. what luck! I was using a small block of steel with a hole drilled in it just big enough to slip over the barrel nut. it has a small hole drilled in the side to slide a pin thru to the side hole in the nut. has worked well in the past. needless to say I need a barrel nut for 35 rem with 50 serrations. any help?

Fred
Posts: 133
Joined: Wed Feb 26, 2014 11:10 pm

Re: Need buffer spring for .35 remington

Post by Fred »

Yeesh. That's no bueno.

I don't have a spare barrel nut. They must be hard if it cracked in thirds.

Nummrich says they have one or more. It's anyone's guess on the condition though:
https://www.gunpartscorp.com/products/836000

Maybe fleabay too.

As far as bolt-travel goes, just pulling the handle all the way back to cock it, the bolt carrier contacts the rear of the receiver on my 81. It's not hammered or peened, but the contact's there.

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