Aluminun Breech
With all the talk of brass and aluminum breeches, I started making one that I think will work with no problems. Had enough time to turn the OD, drill the hole, ream it and cut the step like the stock one. If I get home early enough I will stick my o ring tool in a holder and cut the o ring grove.
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The key factor is that the Aluminum Breech does exert ~15% more Force to the TopHat, even though the velocity is lower. I dont’ see any difference in timing as either a Delrin or Aluminum Breech both reach maximum velocity at 0.013 seconds.
(NOTE: In the simulation I have 3000 psi against the tophat and that is not correct as I should have calculated the actual dimension of the area of the bottom of the valve delrin and found the reciprocal which is 1/.11 = 9 and divide 3000 by 9 to get 333 psi)
There’s my 2 cents – (I’ll keep fiddling with this)
Delrin Breech
Aluminum Breech
Seeing that delrin and aluminum have a difference of 33x (450,000/15,000,000) in the moe.
Something tells me the difference between the two real world components will not be that drastic and if anything noticeable at all. This being for an aluminum breech that is the exact same weight and length as the delrin breech. The reason being is that the forces involved are super small and the valve is anything but a precision part.
Yes, no? 😀
Nifty program you have there. 😯
I have searched for a program to compare Modulus of Elasticity and Rigidity of two objects in Collision and I understand it is very complex and can’t find such unfortunately. I can use the Elasticity Coefficient but that is not really what you are talking about.
You know who would have that – Jerry
I’d be interested to see what the program spits out for the same weight breeches in the two different materials compared to real world tests for the actual components…
Seeing that delrin and aluminum have a difference of 33x (450,000/15,000,000) in the moe.
Something tells me the difference between the two real world components will not be that drastic and if anything noticeable at all. This being for an aluminum breech that is the exact same weight and length as the delrin breech. The reason being is that the forces involved are super small and the valve is anything but a precision part.
Yes, no? 😀
Nifty program you have there. 😯
It’s all about the weight right? 😕 (edit, oh, the post is now gone) In compression both the materials will transmit the force of the hammer about the same to the tophat.
I looked up the weight of average Delrin and Aluminum and Brass and found the weight factor is 1-2-6, so I doubled the weight of the Delrin breech. I would have multiplied by 6 if it was a Brass breech.
Weight and the Modulus of Elasticity.
Weight is a factor and can be positive or negative, as heavier objects will absorb more energy but not velocity to get them in motion so a heavier Aluminum breech is slower.
The key is the Elasticity. Maybe you have seen a steel ball and a rubber ball bounced off a steel plate and wondered why the steel ball bounces higher ? Transfer of Energy and Momentum through the steel ball is higher.
Delrin has a MoE of 450,000 and Aluminum has a MoE of 15,000,000.
A higher MoE will transfer Energy and Momentum more efficiently.
I pulled my post as something confused me on one of the graphs and I will repost.
AG1, how did you figure the weight of the aluminum breech?
It’s all about the weight right? 😕 (edit, oh, the post is now gone) In compression both the materials will transmit the force of the hammer about the same to the tophat.
And why not lighten the aluminum breech to the same weight as the delrin breech and even out the load difference between the two. 😉
Except he wants the extra weight to produce higher power…
Have you tried running the numbers on something that produces 10% difference in the fancy programs and then chrony’d the gun to see if it even matters? I’d be really interested to see if the rifle actually does what the math says it should or if it’s totally irrelevant at the small increments.
I’m making it for strength. Sooner or later my stock breech is going to fail. These guns were not designed to make 200 fpe. I think we are going well beyond what they were engineered for.
It will be black hard anodize. Far as I know R&L valve uses the stock tophat or it wouldn’t work with your stock breech. It will be a copy of the stock breech exept it will have the larger 90 d o rings.
Will you also Black anodize them ?
Will you have some drilled for SubSonnics Bolt handle ?
Will your design have enough play to be used on a R&L Extreme valve as those are custom tophats ?
Because it is still has to slide on the barrel. That way there is no chance of wear.
Why hard anodizing ? It’s definitely harder than delrin by a factor of 33, I believe.
Tension Elasticity Modulus for Delrin is 450,000 and for average Aluminum is 15,000,000 (I think – I know those aren’t Brinnell numbers)
Looks like $55.00 shipped. Hard anodizing is the issue with price. If it’s all good I wil make 10. $108.00 lot charge for hard anodizing.
That looks like a winner – how much will you sell for ?
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Are those graphs with different breech weights?
On no, I see what your saying now… Those are for the two different breech weights, the program doesn’t cover the thing i’m talking about…
Still pretty sweet. 😉