Changing Springs and Buffers in My Beowulfs To Improve Reliability

Okay, so the last range trip went a lot better. The new Lancer L5AWM mags with Tromix followers worked great. The reliability on the pistol was coming along but not where I wanted it and the rifle was disappointing still but I knew what was going on.

7.5″ Beowulf Buffer Spring

My 7.5″ Beowulf pistol is running pretty well but I wanted to increase the forward force of the bolt carrier to strip the next round and chamber it. I was already running an H2 buffer but an other wise normal carbine spring. I upped my game to a Sprinco Red Extra Power Carbine buffer spring that they say is made with the “thumper” cartridges such as the .458 SOCOM, .450 Bushmaster, .50 Beowulf. I bought mine from Primary Arms.

The Mil-Spec Carbine Buffer Spring is on top. The Extra Power spring is on the bottom with one end painted red. That’s handy for knowing what spring is in the weapon at a glance.

I cleaned the pistol, lubed everything and installed the extra power spring and the H2 buffer that was in there. It definitely slammed home harder when I released the bolt.

When we go to the range next, I’ll be taking a standard carbine spring, an enhanced Sprinco spring and the carbine already has the extra power spring already installed. I’m also taking standard, H2 and H3 buffers with me.

Changed the Spring and the Buffer on my Full Size Beowulf Rifle

This rifle was built using an Alexander Arms DIY upper.

When we were shooting this, it had a hard time stripping the next round and chambering it. It dawned on me that they hydraulic buffer that I originally used wasn’t driving the bolt carrier forward hard enough. You see, a Hydraulic buffer has a piston inside that has a controlled leak down rate and, for whatever reason, it was dampening the stripping of the next round properly.

With carbine tubes, you have tons of sling and buffer options. Not so much on rifle length tubes. I did opt for a Geiselle Super 42 rifle-length buffer spring and a slightly heavier Expo Arms 5.4 oz rifle buffer –I bought both from Primary Arms.

Top: KynSHOT hydraulic buffer and Mil-Spec rifle-length buffer spring.
Bottom: Expo Arms 5.4oz buffer and Geiselle Super 42 Rifle-length buffer spring
The Kynshot buffer is very nicely made but I don’t think it’s the best choice for this application. I will save it for future projects.

When I cleaned the rifle prior to installing the new spring and buffer, the one surprising thing I found was that it was fairly dry. Why? I have no idea and this would have impacted functionality at the range also as I assumed I’d lubed it already before putting it away. Yet another example of my memory not being what it used to be.

Given that surprise, I went through and applied Super Lube oil and grease before installing the new Geiselle spring and Expo buffer. Afterwards, the action slammed home very easily.

I will take the hydraulic buffer with me back to the range for testing but am somewhat skeptical of it right now. The rifle is set for the next range visit at this point. Another Mil-Spec spring and buffer will be in the bag as well.


We have a ton of snow right now and I’ll have to wait to test my hypotheses. I expect that with the above changes, the two Beowulfs will run very well now.

I hope this helps you out!

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