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why dose a single stack fed upper have m4 feed ramps?? — 1 Answer

by bushben, from MN, United States Asked on September 22, 2018

Name GLFA AR-15 Complete Upper .450 Bushmaster 18in, S/S (4.2)
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Answered by Ethan C., Gear Expert, from IL, United States, on February 07, 2019

.450 Bushmaster can also be used in standard milspec AR-15 upper receivers (albeit with an enlarged ejection port), so the .450 Bushmaster round works well with standard M4 feed ramps. To save money, most companies making a .450 Bushmaster upper receiver simply take an AR-15 upper receiver and mill out the ejection port rather than having to custom-make a completely different upper receiver. This saves them a great deal of money in production costs.

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